diff --git a/browser/themes/linux/pageInfo.css b/browser/themes/linux/pageInfo.css
index 47f5fe544e0c..ec2d6ab3e710 100644
--- a/browser/themes/linux/pageInfo.css
+++ b/browser/themes/linux/pageInfo.css
@@ -21,6 +21,10 @@
   color: HighlightText;
 }
 
+#viewGroup > radio > .radio-label-box {
+  padding: 0 6px;
+}
+
 #topBar {
   border-bottom: 1px solid ThreeDShadow;
   padding-inline-start: 10px;
diff --git a/browser/themes/osx/pageInfo.css b/browser/themes/osx/pageInfo.css
index 6c9f1121620a..87339a8bda9f 100644
--- a/browser/themes/osx/pageInfo.css
+++ b/browser/themes/osx/pageInfo.css
@@ -27,7 +27,7 @@
   font: menu;
   text-shadow: @loweredShadow@;
   margin: 0;
-  padding: 0 1px;
+  padding: 0 6px;
   height: 22px;
 }
 
diff --git a/browser/themes/osx/syncedtabs/sidebar.css b/browser/themes/osx/syncedtabs/sidebar.css
index e56955563ce2..c92deb3f4089 100644
--- a/browser/themes/osx/syncedtabs/sidebar.css
+++ b/browser/themes/osx/syncedtabs/sidebar.css
@@ -100,6 +100,10 @@
   }
 }
 
+.sidebar-search-container {
+  padding: 4px;
+}
+
 .search-box {
   -moz-appearance: searchfield;
   padding: 1px;
@@ -111,7 +115,7 @@
   text-shadow: none;
 }
 
-.search-box.compact > .textbox-input-box > .textbox-search-icons > .textbox-search-clear {
+.search-box > .textbox-input-box > .textbox-search-icons > .textbox-search-clear {
   background-image: url(chrome://global/skin/icons/searchfield-cancel.svg);
   background-repeat: no-repeat;
   background-size: 11px 11px;
@@ -119,12 +123,6 @@
   height: 11px;
 }
 
-.search-box.compact {
-    padding: 0px;
-    /* font size is in px because the XUL it was copied from uses px */
-    font-size: 11px;
-}
-
 .textbox-search-clear {
   margin-top: 1px;
 }
diff --git a/browser/themes/windows/pageInfo.css b/browser/themes/windows/pageInfo.css
index b0819437509f..a2948cec8c5c 100644
--- a/browser/themes/windows/pageInfo.css
+++ b/browser/themes/windows/pageInfo.css
@@ -12,9 +12,9 @@
 #viewGroup > radio {
   list-style-image: url("chrome://browser/skin/pageInfo.png");
   -moz-appearance: none;
-  padding: 5px 3px 1px 3px;
-  margin: 0 1px;
   min-width: 4.5em;
+  margin: 0;
+  padding: 3px;
 }
 
 #viewGroup > radio:hover {
@@ -27,6 +27,11 @@
   color: black;
 }
 
+#viewGroup > radio > .radio-label-box {
+  margin: 0;
+  padding: 0 6px;
+}
+
 #topBar {
   border-bottom: 1px solid ThreeDLightShadow;
   padding-inline-start: 10px;
diff --git a/build/pgo/server-locations.txt b/build/pgo/server-locations.txt
index 44d5a043e924..75a92471125e 100644
--- a/build/pgo/server-locations.txt
+++ b/build/pgo/server-locations.txt
@@ -289,9 +289,5 @@ https://tls1.example.com:443        privileged,tls1
 # Hosts for youtube rewrite tests
 https://mochitest.youtube.com:443
 
-# Hosts for stylo blocklist tests
-http://stylo-blocklist.com:80          privileged
-http://test.stylo-blocklist.com:80     privileged
-
 # Host for U2F localhost tests
 https://localhost:443
diff --git a/devtools/client/themes/boxmodel.css b/devtools/client/themes/boxmodel.css
index 41bd3b6b64a7..aae4d5d3bea7 100644
--- a/devtools/client/themes/boxmodel.css
+++ b/devtools/client/themes/boxmodel.css
@@ -303,6 +303,7 @@
 .boxmodel-editable {
   border: 1px dashed transparent;
   -moz-user-select: none;
+  white-space: nowrap;
 }
 
 .boxmodel-editable:hover {
diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index fce2b3fe8d84..93040c4926c0 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -4445,24 +4445,6 @@ nsDOMWindowUtils::GetIsStyledByServo(bool* aStyledByServo)
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsDOMWindowUtils::AddToStyloBlocklist(const nsACString& aBlockedDomain)
-{
-#ifdef MOZ_STYLO
-  nsLayoutUtils::AddToStyloBlocklist(aBlockedDomain);
-#endif
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsDOMWindowUtils::RemoveFromStyloBlocklist(const nsACString& aBlockedDomain)
-{
-#ifdef MOZ_STYLO
-  nsLayoutUtils::RemoveFromStyloBlocklist(aBlockedDomain);
-#endif
-  return NS_OK;
-}
-
 NS_INTERFACE_MAP_BEGIN(nsTranslationNodeList)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
   NS_INTERFACE_MAP_ENTRY(nsITranslationNodeList)
diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index 530e3f4806a6..b990b73dde83 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -13238,7 +13238,7 @@ nsIDocument::UpdateStyleBackendType()
 
 #ifdef MOZ_STYLO
   if (nsLayoutUtils::StyloEnabled() &&
-      nsLayoutUtils::ShouldUseStylo(mDocumentURI, NodePrincipal())) {
+      nsLayoutUtils::ShouldUseStylo(NodePrincipal())) {
     mStyleBackendType = StyleBackendType::Servo;
   }
 #endif
@@ -13902,30 +13902,11 @@ nsDocument::IsThirdParty()
   return mIsThirdParty.value();
 }
 
-static bool
-IsAboutReader(nsIURI* aURI)
-{
-  if (!aURI) {
-    return false;
-  }
-
-  nsCString spec;
-  aURI->GetSpec(spec);
-
-  // Reader mode URLs look like about:reader?[...].
-  return StringBeginsWith(spec, NS_LITERAL_CSTRING("about:reader"));
-}
-
 bool
 nsIDocument::IsScopedStyleEnabled()
 {
   if (mIsScopedStyleEnabled == eScopedStyle_Unknown) {
-    // We allow <style scoped> in about:reader pages since on Android
-    // we use it to inject some in-page UI.  (We currently don't
-    // support styling about:reader pages in stylo anyway, so for
-    // now it's OK to enable it here.)
     mIsScopedStyleEnabled = nsContentUtils::IsChromeDoc(this) ||
-                            IsAboutReader(mDocumentURI) ||
                             nsContentUtils::IsScopedStylePrefEnabled()
                               ? eScopedStyle_Enabled
                               : eScopedStyle_Disabled;
diff --git a/dom/interfaces/base/nsIDOMWindowUtils.idl b/dom/interfaces/base/nsIDOMWindowUtils.idl
index fa603f7aa0ce..651e537bbd2e 100644
--- a/dom/interfaces/base/nsIDOMWindowUtils.idl
+++ b/dom/interfaces/base/nsIDOMWindowUtils.idl
@@ -1980,20 +1980,6 @@ interface nsIDOMWindowUtils : nsISupports {
    */
   readonly attribute boolean isStyledByServo;
 
-  /**
-   * Add a domain to the existing stylo blocklist.
-   *
-   * This calls nsLayoutUtils::AddToStyloBlocklist().
-   */
-  void addToStyloBlocklist(in ACString aBlockedDomain);
-
-  /**
-   * Remove a domain from the existing stylo blocklist.
-   *
-   * This calls nsLayoutUtils::RemoveFromStyloBlocklist().
-   */
-  void removeFromStyloBlocklist(in ACString aBlockedDomain);
-
   /**
    * Capture the contents of the current WebRender frame and
    * save them to a folder relative to the current working directory.
diff --git a/dom/ipc/ContentPrefs.cpp b/dom/ipc/ContentPrefs.cpp
index 45e9f505e05d..a5dbfed1a37d 100644
--- a/dom/ipc/ContentPrefs.cpp
+++ b/dom/ipc/ContentPrefs.cpp
@@ -178,10 +178,6 @@ const char* mozilla::dom::ContentPrefs::gEarlyPrefs[] = {
   "layout.css.servo.enabled",
 #endif
   "layout.css.shape-outside.enabled",
-#ifdef MOZ_STYLO
-  "layout.css.stylo-blocklist.blocked_domains",
-  "layout.css.stylo-blocklist.enabled",
-#endif
   "layout.css.text-align-unsafe-value.enabled",
   "layout.css.text-combine-upright-digits.enabled",
   "layout.css.text-combine-upright.enabled",
diff --git a/dom/media/AudioStream.cpp b/dom/media/AudioStream.cpp
index ce6fb2f3bc8d..dcabdb877c36 100644
--- a/dom/media/AudioStream.cpp
+++ b/dom/media/AudioStream.cpp
@@ -350,6 +350,7 @@ AudioStream::Init(uint32_t aNumChannels, uint32_t aChannelMap, uint32_t aRate)
   params.channels = mOutChannels;
   params.layout = CubebUtils::ConvertChannelMapToCubebLayout(aChannelMap);
   params.format = ToCubebFormat<AUDIO_OUTPUT_FORMAT>::value;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   mAudioClock.Init(aRate);
 
diff --git a/dom/media/GraphDriver.cpp b/dom/media/GraphDriver.cpp
index f37568e21816..f39f51913c04 100644
--- a/dom/media/GraphDriver.cpp
+++ b/dom/media/GraphDriver.cpp
@@ -627,6 +627,7 @@ AudioCallbackDriver::Init()
 
   output.channels = mOutputChannels;
   output.layout = CubebUtils::GetPreferredChannelLayoutOrSMPTE(cubebContext, mOutputChannels);
+  output.prefs = CUBEB_STREAM_PREF_NONE;
 
   Maybe<uint32_t> latencyPref = CubebUtils::GetCubebMSGLatencyInFrames();
   if (latencyPref) {
diff --git a/dom/xul/nsXULElement.cpp b/dom/xul/nsXULElement.cpp
index c248a142bad6..71f42232e0bb 100644
--- a/dom/xul/nsXULElement.cpp
+++ b/dom/xul/nsXULElement.cpp
@@ -2339,7 +2339,7 @@ nsXULPrototypeElement::SetAttrAt(uint32_t aPos, const nsAString& aValue,
 
         RefPtr<DeclarationBlock> declaration;
         if (nsLayoutUtils::StyloEnabled() &&
-            nsLayoutUtils::ShouldUseStylo(aDocumentURI, principal)) {
+            nsLayoutUtils::ShouldUseStylo(principal)) {
           RefPtr<URLExtraData> data =
             new URLExtraData(aDocumentURI, aDocumentURI, principal);
           declaration = ServoDeclarationBlock::FromCssText(
diff --git a/layout/base/nsLayoutUtils.cpp b/layout/base/nsLayoutUtils.cpp
index f35d40852085..3c4012e26752 100644
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -129,7 +129,6 @@
 #include "DisplayListChecker.h"
 #include "TextDrawTarget.h"
 #include "nsDeckFrame.h"
-#include "nsIEffectiveTLDService.h" // for IsInStyloBlocklist
 #include "mozilla/StylePrefs.h"
 #include "mozilla/dom/InspectorFontFace.h"
 
@@ -196,8 +195,6 @@ typedef nsStyleTransformMatrix::TransformReferenceBox TransformReferenceBox;
 /* static */ bool nsLayoutUtils::sTextCombineUprightDigitsEnabled;
 #ifdef MOZ_STYLO
 /* static */ bool nsLayoutUtils::sStyloEnabled;
-/* static */ bool nsLayoutUtils::sStyloBlocklistEnabled;
-/* static */ nsTArray<nsCString>* nsLayoutUtils::sStyloBlocklist = nullptr;
 #endif
 /* static */ uint32_t nsLayoutUtils::sIdlePeriodDeadlineLimit;
 /* static */ uint32_t nsLayoutUtils::sQuiescentFramesBeforeIdlePeriod;
@@ -8231,24 +8228,6 @@ nsLayoutUtils::Initialize()
     Preferences::AddBoolVarCache(&sStyloEnabled,
                                  "layout.css.servo.enabled");
   }
-  // We should only create the blocklist ONCE, and ignore any blocklist
-  // reloads happen. Because otherwise we could have a top level page that
-  // uses Stylo (if its load happens before the blocklist reload) and a
-  // child iframe that uses Gecko (if its load happens after the blocklist
-  // reload). If some page contains both backends, and they try to move
-  // element across backend boundary, it could crash (see bug 1404020).
-  sStyloBlocklistEnabled =
-    Preferences::GetBool("layout.css.stylo-blocklist.enabled");
-  if (sStyloBlocklistEnabled && !sStyloBlocklist) {
-    nsAutoCString blocklist;
-    Preferences::GetCString("layout.css.stylo-blocklist.blocked_domains", blocklist);
-    if (!blocklist.IsEmpty()) {
-      sStyloBlocklist = new nsTArray<nsCString>;
-      for (const nsACString& domainString : blocklist.Split(',')) {
-        sStyloBlocklist->AppendElement(domainString);
-      }
-    }
-  }
 #endif
   Preferences::AddUintVarCache(&sIdlePeriodDeadlineLimit,
                                "layout.idle_period.time_limit",
@@ -8271,13 +8250,7 @@ nsLayoutUtils::Shutdown()
     delete sContentMap;
     sContentMap = nullptr;
   }
-#ifdef MOZ_STYLO
-  if (sStyloBlocklist) {
-    sStyloBlocklist->Clear();
-    delete sStyloBlocklist;
-    sStyloBlocklist = nullptr;
-  }
-#endif
+
   for (auto& callback : kPrefCallbacks) {
     Preferences::UnregisterCallback(callback.func, callback.name);
   }
@@ -8290,7 +8263,7 @@ nsLayoutUtils::Shutdown()
 #ifdef MOZ_STYLO
 /* static */
 bool
-nsLayoutUtils::ShouldUseStylo(nsIURI* aDocumentURI, nsIPrincipal* aPrincipal)
+nsLayoutUtils::ShouldUseStylo(nsIPrincipal* aPrincipal)
 {
   // Disable stylo for system principal because XUL hasn't been fully
   // supported. Other principal aren't able to use XUL by default, and
@@ -8300,84 +8273,10 @@ nsLayoutUtils::ShouldUseStylo(nsIURI* aDocumentURI, nsIPrincipal* aPrincipal)
       nsContentUtils::IsSystemPrincipal(aPrincipal)) {
     return false;
   }
-  // Check any internal page which we need to explicitly blacklist.
-  if (aDocumentURI) {
-    bool isAbout = false;
-    if (NS_SUCCEEDED(aDocumentURI->SchemeIs("about", &isAbout)) && isAbout) {
-      nsAutoCString path;
-      aDocumentURI->GetFilePath(path);
-      // about:reader requires support of scoped style, so we have to
-      // use Gecko backend for now. See bug 1402094.
-      // This should be fixed by bug 1204818.
-      if (path.EqualsLiteral("reader")) {
-        return false;
-      }
-    }
-  }
-  // Check the stylo block list.
-  if (IsInStyloBlocklist(aPrincipal)) {
-    return false;
-  }
+
   return true;
 }
 
-/* static */
-bool
-nsLayoutUtils::IsInStyloBlocklist(nsIPrincipal* aPrincipal)
-{
-  if (!sStyloBlocklist) {
-    return false;
-  }
-
-  // Note that a non-codebase principal (eg the system principal) will return
-  // a null URI.
-  nsCOMPtr<nsIURI> codebaseURI;
-  aPrincipal->GetURI(getter_AddRefs(codebaseURI));
-  if (!codebaseURI) {
-    return false;
-  }
-
-  nsCOMPtr<nsIEffectiveTLDService> tldService =
-    do_GetService(NS_EFFECTIVETLDSERVICE_CONTRACTID);
-  NS_ENSURE_TRUE(tldService, false);
-
-  // Check if a document's eTLD+1 domain belongs to one of the stylo blocklist.
-  nsAutoCString baseDomain;
-  NS_SUCCEEDED(tldService->GetBaseDomain(codebaseURI, 0, baseDomain));
-  for (const nsCString& domains : *sStyloBlocklist) {
-    if (baseDomain.Equals(domains)) {
-      return true;
-    }
-  }
-  return false;
-}
-
-/* static */
-void
-nsLayoutUtils::AddToStyloBlocklist(const nsACString& aBlockedDomain)
-{
-  if (!sStyloBlocklist) {
-    sStyloBlocklist = new nsTArray<nsCString>;
-  }
-  sStyloBlocklist->AppendElement(aBlockedDomain);
-}
-
-/* static */
-void
-nsLayoutUtils::RemoveFromStyloBlocklist(const nsACString& aBlockedDomain)
-{
-  if (!sStyloBlocklist) {
-    return;
-  }
-
-  sStyloBlocklist->RemoveElement(aBlockedDomain);
-
-  if (sStyloBlocklist->IsEmpty()) {
-    delete sStyloBlocklist;
-    sStyloBlocklist = nullptr;
-  }
-}
-
 /* static */
 bool
 nsLayoutUtils::StyloChromeEnabled()
diff --git a/layout/base/nsLayoutUtils.h b/layout/base/nsLayoutUtils.h
index cf6cadf3495f..2f844ce6fe18 100644
--- a/layout/base/nsLayoutUtils.h
+++ b/layout/base/nsLayoutUtils.h
@@ -2582,35 +2582,11 @@ public:
 
 #ifdef MOZ_STYLO
   /**
-   * Return whether stylo should be used for a given document URI and
-   * principal.
+   * Return whether stylo should be used for a given document principal.
    */
-  static bool ShouldUseStylo(nsIURI* aDocumentURI, nsIPrincipal* aPrincipal);
-
-  /**
-   * Principal-based blocklist for stylo.
-   * Check if aPrincipal is blocked by stylo's blocklist and should fallback to
-   * use Gecko's style backend. Note that using a document's principal rather
-   * than the document URI will let us piggy-back off the existing principal
-   * relationships and symmetries.
-   */
-  static bool IsInStyloBlocklist(nsIPrincipal* aPrincipal);
-
-  /**
-   * Add aBlockedDomain to the existing stylo blocklist, i.e., sStyloBlocklist.
-   * This function is exposed to nsDOMWindowUtils and only for testing purpose.
-   * So, NEVER use this in any other cases.
-   */
-  static void AddToStyloBlocklist(const nsACString& aBlockedDomain);
-
-  /**
-   * Remove aBlockedDomain from the existing stylo blocklist, i.e., sStyloBlocklist.
-   * This function is exposed to nsDOMWindowUtils and only for testing purpose.
-   * So, NEVER use this in any other cases.
-   */
-  static void RemoveFromStyloBlocklist(const nsACString& aBlockedDomain);
+  static bool ShouldUseStylo(nsIPrincipal* aPrincipal);
 #else
-  static bool ShouldUseStylo(nsIURI* aDocumentURI, nsIPrincipal* aPrincipal) {
+  static bool ShouldUseStylo(nsIPrincipal* aPrincipal) {
     return false;
   }
 #endif
@@ -3134,8 +3110,6 @@ private:
   static bool sTextCombineUprightDigitsEnabled;
 #ifdef MOZ_STYLO
   static bool sStyloEnabled;
-  static bool sStyloBlocklistEnabled;
-  static nsTArray<nsCString>* sStyloBlocklist;
 #endif
   static uint32_t sIdlePeriodDeadlineLimit;
   static uint32_t sQuiescentFramesBeforeIdlePeriod;
diff --git a/layout/style/test/mochitest.ini b/layout/style/test/mochitest.ini
index 5bff0f649251..18ceedf03c77 100644
--- a/layout/style/test/mochitest.ini
+++ b/layout/style/test/mochitest.ini
@@ -304,15 +304,6 @@ skip-if = toolkit == 'android' #bug 775227
 [test_stylesheet_additions.html]
 skip-if = !stylo
 [test_stylesheet_clone_font_face.html]
-[test_stylo_blocklist-01.html]
-support-files = stylo_blocked_domain_page.html
-skip-if = !stylo # no need to test blocklist for non-stylo platforms
-[test_stylo_blocklist-02.html]
-support-files = stylo_blocked_domain_page.html
-skip-if = !stylo # no need to test blocklist for non-stylo platforms
-[test_stylo_blocklist-03.html]
-support-files = stylo_non_blocked_domain_page.html
-skip-if = !stylo # no need to test blocklist for non-stylo platforms
 [test_supports_rules.html]
 [test_system_font_serialization.html]
 [test_text_decoration_shorthands.html]
diff --git a/layout/style/test/stylo_blocked_domain_page.html b/layout/style/test/stylo_blocked_domain_page.html
deleted file mode 100644
index 49d524a10183..000000000000
--- a/layout/style/test/stylo_blocked_domain_page.html
+++ /dev/null
@@ -1,13 +0,0 @@
-<!DOCTYPE html>
-<head>
-  <title>Test page with a mock domain which is listed in the stylo blocklist</title>
-</head>
-<script>
-window.onload = function() {
-  if (SpecialPowers.getDOMWindowUtils(window).isStyledByServo == false) {
-    opener.postMessage("TEST-PASS", "*");
-  } else {
-    opener.postMessage("TEST-FAIL", "*");
-  }
-}
-</script>
diff --git a/layout/style/test/stylo_non_blocked_domain_page.html b/layout/style/test/stylo_non_blocked_domain_page.html
deleted file mode 100644
index ff54ef53e7af..000000000000
--- a/layout/style/test/stylo_non_blocked_domain_page.html
+++ /dev/null
@@ -1,13 +0,0 @@
-<!DOCTYPE html>
-<head>
-  <title>Test page with a mock domain which is NOT listed in the stylo blocklist</title>
-</head>
-<script>
-window.onload = function() {
-  if (SpecialPowers.getDOMWindowUtils(window).isStyledByServo == true) {
-    opener.postMessage("TEST-PASS", "*");
-  } else {
-    opener.postMessage("TEST-FAIL", "*");
-  }
-}
-</script>
diff --git a/layout/style/test/test_stylo_blocklist-01.html b/layout/style/test/test_stylo_blocklist-01.html
deleted file mode 100644
index 990ded81bb67..000000000000
--- a/layout/style/test/test_stylo_blocklist-01.html
+++ /dev/null
@@ -1,24 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test the mechanism of stylo blocklist</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<script>
-SimpleTest.waitForExplicitFinish();
-SpecialPowers.getDOMWindowUtils(window).addToStyloBlocklist("stylo-blocklist.com");
-let win =
-  window.open("http://stylo-blocklist.com/tests/layout/style/test/stylo_blocked_domain_page.html", "");
-window.onmessage = function (evt) {
-  is(evt.data, "TEST-PASS",
-     "Document with blocked domain should not use servo backend");
-  win.close();
-  SpecialPowers.getDOMWindowUtils(window).removeFromStyloBlocklist("stylo-blocklist.com");
-  SimpleTest.finish();
-}
-</script>
-</pre>
-</body>
-</html>
diff --git a/layout/style/test/test_stylo_blocklist-02.html b/layout/style/test/test_stylo_blocklist-02.html
deleted file mode 100644
index b2b145c360ac..000000000000
--- a/layout/style/test/test_stylo_blocklist-02.html
+++ /dev/null
@@ -1,24 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test the mechanism of stylo blocklist</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<script>
-SimpleTest.waitForExplicitFinish();
-SpecialPowers.getDOMWindowUtils(window).addToStyloBlocklist("stylo-blocklist.com");
-let win =
-  window.open("http://test.stylo-blocklist.com/tests/layout/style/test/stylo_blocked_domain_page.html", "");
-window.onmessage = function (evt) {
-  is(evt.data, "TEST-PASS",
-     "Document with blocked sub-domain should not use servo backend");
-  win.close();
-  SpecialPowers.getDOMWindowUtils(window).removeFromStyloBlocklist("stylo-blocklist.com");
-  SimpleTest.finish();
-}
-</script>
-</pre>
-</body>
-</html>
diff --git a/layout/style/test/test_stylo_blocklist-03.html b/layout/style/test/test_stylo_blocklist-03.html
deleted file mode 100644
index 37e77da72ee0..000000000000
--- a/layout/style/test/test_stylo_blocklist-03.html
+++ /dev/null
@@ -1,25 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test the mechanism of stylo blocklist</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<script>
-SimpleTest.waitForExplicitFinish();
-// "http://example.com" should not be in the blocklist by any chance. Adding this
-// line is just for safety, and it also makes this test more readable.
-SpecialPowers.getDOMWindowUtils(window).removeFromStyloBlocklist("example.com");
-let win =
-  window.open("http://example.com/tests/layout/style/test/stylo_non_blocked_domain_page.html", "");
-window.onmessage = function (evt) {
-  is(evt.data, "TEST-PASS",
-     "Document without blocked domain should use servo backend");
-  win.close();
-  SimpleTest.finish();
-}
-</script>
-</pre>
-</body>
-</html>
diff --git a/media/audioipc/README_MOZILLA b/media/audioipc/README_MOZILLA
index a22749478f07..9e0652c57bde 100644
--- a/media/audioipc/README_MOZILLA
+++ b/media/audioipc/README_MOZILLA
@@ -5,4 +5,4 @@ Makefile.in build files for the Mozilla build system.
 
 The audioipc-2 git repository is: https://github.com/djg/audioipc-2.git
 
-The git commit ID used was 71cc67f44b803e0288997247c060375196f1cf9b (2018-01-19 17:16:33 +1000)
+The git commit ID used was d7798606aa590ef402344b7a519a0053725a9805 (2018-01-27 09:07:03 +1000)
diff --git a/media/audioipc/audioipc/Cargo.toml b/media/audioipc/audioipc/Cargo.toml
index 308cb5c6f169..32924feb9ae5 100644
--- a/media/audioipc/audioipc/Cargo.toml
+++ b/media/audioipc/audioipc/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "audioipc"
-version = "0.2.0"
+version = "0.2.1"
 authors = [
         "Matthew Gregan <kinetik@flim.org>",
         "Dan Glastonbury <dan.glastonbury@gmail.com>"
diff --git a/media/audioipc/audioipc/src/messages.rs b/media/audioipc/audioipc/src/messages.rs
index 68f468391316..7cf7b06c1f70 100644
--- a/media/audioipc/audioipc/src/messages.rs
+++ b/media/audioipc/audioipc/src/messages.rs
@@ -122,7 +122,8 @@ pub struct StreamParams {
     pub format: u32,
     pub rate: u16,
     pub channels: u8,
-    pub layout: i32
+    pub layout: i32,
+    pub prefs: i32
 }
 
 impl<'a> From<&'a ffi::cubeb_stream_params> for StreamParams {
@@ -133,7 +134,8 @@ impl<'a> From<&'a ffi::cubeb_stream_params> for StreamParams {
             format: params.format,
             rate: params.rate as u16,
             channels: params.channels as u8,
-            layout: params.layout
+            layout: params.layout,
+            prefs: params.prefs
         }
     }
 }
@@ -144,7 +146,8 @@ impl<'a> From<&'a StreamParams> for ffi::cubeb_stream_params {
             format: params.format,
             rate: u32::from(params.rate),
             channels: u32::from(params.channels),
-            layout: params.layout
+            layout: params.layout,
+            prefs: params.prefs
         }
     }
 }
diff --git a/media/audioipc/gecko.patch b/media/audioipc/gecko.patch
index edaa535edc6c..d3ebdebf7d0a 100644
--- a/media/audioipc/gecko.patch
+++ b/media/audioipc/gecko.patch
@@ -49,7 +49,7 @@ index 5b79b83..01463be 100644
  [dependencies]
  audioipc = { path = "../audioipc" }
 -cubeb-core = { git = "https://github.com/djg/cubeb-rs", version="^0.1" }
--cubeb = { git = "https://github.com/djg/cubeb-rs", version="^0.3.1" }
+-cubeb = { git = "https://github.com/djg/cubeb-rs", version="^0.3.2" }
 +cubeb-core = { path = "../../cubeb-rs/cubeb-core" }
 +cubeb = { path = "../../cubeb-rs/cubeb-api" }
  bytes = "0.4"
diff --git a/media/audioipc/server/Cargo.toml b/media/audioipc/server/Cargo.toml
index 01463be6e638..f38737daa8fb 100644
--- a/media/audioipc/server/Cargo.toml
+++ b/media/audioipc/server/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "audioipc-server"
-version = "0.2.0"
+version = "0.2.1"
 authors = [
         "Matthew Gregan <kinetik@flim.org>",
         "Dan Glastonbury <dan.glastonbury@gmail.com>"
diff --git a/media/cubeb-rs/README_MOZILLA b/media/cubeb-rs/README_MOZILLA
index bb4c649f8bfb..496f8c2c17e1 100644
--- a/media/cubeb-rs/README_MOZILLA
+++ b/media/cubeb-rs/README_MOZILLA
@@ -5,4 +5,4 @@ Makefile.in build files for the Mozilla build system.
 
 The cubeb-rs git repository is: https://github.com/djg/cubeb-rs.git
 
-The git commit ID used was aaba6b34368db990d3ec165ebc85053f61097bac (2017-10-19 15:43:50 +1000)
+The git commit ID used was c7e5ef006dede18158582246bddafbb51f832078 (2018-01-25 11:35:14 +1000)
diff --git a/media/cubeb-rs/cubeb-api/Cargo.toml b/media/cubeb-rs/cubeb-api/Cargo.toml
index 0e02214b75e8..2703dd342095 100644
--- a/media/cubeb-rs/cubeb-api/Cargo.toml
+++ b/media/cubeb-rs/cubeb-api/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 
 name = "cubeb"
-version = "0.3.1"
+version = "0.3.2"
 authors = ["Dan Glastonbury <dglastonbury@mozilla.com>"]
 license = "ISC"
 readme = "README.md"
diff --git a/media/cubeb-rs/cubeb-api/src/lib.rs b/media/cubeb-rs/cubeb-api/src/lib.rs
index a79f44177d44..cedaa6d9a01f 100644
--- a/media/cubeb-rs/cubeb-api/src/lib.rs
+++ b/media/cubeb-rs/cubeb-api/src/lib.rs
@@ -27,12 +27,13 @@ pub use context::Context;
 // Re-export cubeb_core types
 pub use cubeb_core::{ChannelLayout, Device, DeviceFormat, DeviceId, DeviceInfo,
                      DeviceState, DeviceType, Error, ErrorCode, LogLevel, Result,
-                     SampleFormat, State, StreamParams};
+                     SampleFormat, State, StreamParams, StreamPrefs};
 pub use cubeb_core::{DEVICE_FMT_F32BE, DEVICE_FMT_F32LE, DEVICE_FMT_S16BE,
                      DEVICE_FMT_S16LE};
 pub use cubeb_core::{DEVICE_PREF_ALL, DEVICE_PREF_MULTIMEDIA, DEVICE_PREF_NONE,
                      DEVICE_PREF_NOTIFICATION, DEVICE_PREF_VOICE};
 pub use cubeb_core::{DEVICE_TYPE_INPUT, DEVICE_TYPE_OUTPUT, DEVICE_TYPE_UNKNOWN};
+pub use cubeb_core::{STREAM_PREF_LOOPBACK, STREAM_PREF_NONE};
 
 use cubeb_core::binding::Binding;
 use cubeb_core::ffi;
diff --git a/media/cubeb-rs/cubeb-api/src/stream.rs b/media/cubeb-rs/cubeb-api/src/stream.rs
index f0e1ca7b0cf7..a753e45e6d20 100644
--- a/media/cubeb-rs/cubeb-api/src/stream.rs
+++ b/media/cubeb-rs/cubeb-api/src/stream.rs
@@ -40,6 +40,7 @@
 //!         .rate(44100)
 //!         .channels(1)
 //!         .layout(cubeb::ChannelLayout::Mono)
+//!         .prefs(cubeb::STREAM_PREF_NONE)
 //!         .take();
 //!
 //!     let stream_init_opts = cubeb::StreamInitOptionsBuilder::new()
@@ -68,9 +69,10 @@
 //! ```
 
 use {Binding, ChannelLayout, Context, Device, DeviceId, Error, Result,
-     SampleFormat, State, StreamParams};
+     SampleFormat, State, StreamParams, StreamPrefs};
+use STREAM_PREF_NONE;
 use ffi;
-use std::{ptr, str};
+use std::ptr;
 use std::ffi::CString;
 use std::os::raw::{c_long, c_void};
 use sys;
@@ -91,7 +93,7 @@ impl SampleType for i16 {
         SampleFormat::S16NE
     }
     fn from_float(x: f32) -> i16 {
-        (x * i16::max_value() as f32) as i16
+        (x * f32::from(i16::max_value())) as i16
     }
 }
 
@@ -118,7 +120,8 @@ pub struct StreamParamsBuilder {
     format: SampleFormat,
     rate: u32,
     channels: u32,
-    layout: ChannelLayout
+    layout: ChannelLayout,
+    prefs: StreamPrefs
 }
 
 impl Default for StreamParamsBuilder {
@@ -133,7 +136,8 @@ impl StreamParamsBuilder {
             format: SampleFormat::S16NE,
             rate: 0,
             channels: 0,
-            layout: ChannelLayout::Undefined
+            layout: ChannelLayout::Undefined,
+            prefs: STREAM_PREF_NONE
         }
     }
 
@@ -157,6 +161,12 @@ impl StreamParamsBuilder {
         self
     }
 
+    pub fn prefs(&mut self, prefs: StreamPrefs) -> &mut Self {
+        self.prefs = prefs;
+        self
+    }
+
+    #[cfg_attr(feature = "cargo-clippy", allow(match_same_arms))]
     pub fn take(&self) -> StreamParams {
         // Convert native endian types to matching format
         let raw_sample_format = match self.format {
@@ -172,7 +182,8 @@ impl StreamParamsBuilder {
                 format: raw_sample_format,
                 rate: self.rate,
                 channels: self.channels,
-                layout: self.layout as ffi::cubeb_channel_layout
+                layout: self.layout as ffi::cubeb_channel_layout,
+                prefs: self.prefs.bits()
             } as *const _)
         }
     }
@@ -291,7 +302,7 @@ where
                 self.raw,
                 &mut device_ptr
             ));
-            Binding::from_raw_opt(device_ptr).ok_or(Error::from_raw(ffi::CUBEB_ERROR))
+            Binding::from_raw_opt(device_ptr).ok_or_else(|| Error::from_raw(ffi::CUBEB_ERROR))
         }
     }
 
@@ -326,7 +337,7 @@ where
             } else {
                 from_raw_parts(input_buffer as *const _, nframes as usize)
             };
-            let mut output: &mut [CB::Frame] = if output_buffer.is_null() {
+            let output: &mut [CB::Frame] = if output_buffer.is_null() {
                 &mut []
             } else {
                 from_raw_parts_mut(output_buffer as *mut _, nframes as usize)
@@ -638,4 +649,21 @@ mod tests {
         let raw = unsafe { &*params.raw() };
         assert_eq!(raw.rate, 44100);
     }
+
+    #[test]
+    fn stream_params_builder_prefs_default() {
+        use cubeb_core::STREAM_PREF_NONE;
+        let params = StreamParamsBuilder::new().take();
+        assert_eq!(params.prefs(), STREAM_PREF_NONE);
+
+    }
+
+    #[test]
+    fn stream_params_builder_prefs() {
+        use cubeb_core::STREAM_PREF_LOOPBACK;
+        let params = StreamParamsBuilder::new()
+            .prefs(STREAM_PREF_LOOPBACK)
+            .take();
+        assert_eq!(params.prefs(), STREAM_PREF_LOOPBACK);
+    }
 }
diff --git a/media/cubeb-rs/cubeb-backend/src/capi.rs b/media/cubeb-rs/cubeb-backend/src/capi.rs
index da8d49bc416c..308c7d814207 100644
--- a/media/cubeb-rs/cubeb-backend/src/capi.rs
+++ b/media/cubeb-rs/cubeb-backend/src/capi.rs
@@ -174,7 +174,7 @@ pub unsafe extern "C" fn capi_stream_start<STM: Stream>(
 ) -> c_int {
     let stm = &*(s as *const STM);
 
-    let _ = _try!(stm.start());
+    _try!(stm.start());
     ffi::CUBEB_OK
 }
 
@@ -183,7 +183,7 @@ pub unsafe extern "C" fn capi_stream_stop<STM: Stream>(
 ) -> c_int {
     let stm = &*(s as *const STM);
 
-    let _ = _try!(stm.stop());
+    _try!(stm.stop());
     ffi::CUBEB_OK
 }
 
@@ -192,7 +192,7 @@ pub unsafe extern "C" fn capi_stream_reset_default_device<STM: Stream>(
 ) -> c_int {
     let stm = &mut *(s as *mut STM);
 
-    let _ = _try!(stm.reset_default_device());
+    _try!(stm.reset_default_device());
     ffi::CUBEB_OK
 }
 
@@ -222,7 +222,7 @@ pub unsafe extern "C" fn capi_stream_set_volume<STM: Stream>(
 ) -> c_int {
     let stm = &mut *(s as *mut STM);
 
-    let _ = _try!(stm.set_volume(volume));
+    _try!(stm.set_volume(volume));
     ffi::CUBEB_OK
 }
 
@@ -232,7 +232,7 @@ pub unsafe extern "C" fn capi_stream_set_panning<STM: Stream>(
 ) -> c_int {
     let stm = &mut *(s as *mut STM);
 
-    let _ = _try!(stm.set_panning(panning));
+    _try!(stm.set_panning(panning));
     ffi::CUBEB_OK
 }
 
@@ -263,7 +263,7 @@ pub unsafe extern "C" fn capi_register_device_collection_changed<CTX: Context>(
 ) -> i32 {
     let ctx = &*(c as *const CTX);
     let devtype = DeviceType::from_bits_truncate(devtype);
-    let _ = _try!(ctx.register_device_collection_changed(
+    _try!(ctx.register_device_collection_changed(
         devtype,
         collection_changed_callback,
         user_ptr
@@ -288,7 +288,7 @@ where
     }
 }
 
-fn opt_cstr<'a, T: 'a>(_anchor: &'a T, ptr: *const c_char) -> Option<&'a CStr> {
+fn opt_cstr<T>(_anchor: &T, ptr: *const c_char) -> Option<&CStr> {
     if ptr.is_null() {
         None
     } else {
diff --git a/media/cubeb-rs/cubeb-backend/src/ffi.rs b/media/cubeb-rs/cubeb-backend/src/ffi.rs
index 1e79192c2105..1752d5336179 100644
--- a/media/cubeb-rs/cubeb-backend/src/ffi.rs
+++ b/media/cubeb-rs/cubeb-backend/src/ffi.rs
@@ -37,23 +37,77 @@ pub struct cubeb_layout_map {
     layout: ffi::cubeb_channel_layout
 }
 
+pub type InitFn =
+    unsafe extern fn(context: *mut *mut ffi::cubeb, context_name: *const c_char) -> c_int;
+pub type GetBackendIdFn =
+    unsafe extern fn(context: *mut ffi::cubeb) -> *const c_char;
+pub type GetMaxChannelCountFn =
+    unsafe extern fn(context: *mut ffi::cubeb, max_channels: *mut u32) -> c_int;
+pub type GetMinLatencyFn =
+    unsafe extern fn(context: *mut ffi::cubeb,
+                     params: ffi::cubeb_stream_params,
+                     latency_ms: *mut u32) -> c_int;
+pub type GetPreferredSampleRateFn =
+    unsafe extern fn(context: *mut ffi::cubeb, rate: *mut u32) -> c_int;
+pub type GetPreferredChannelLayoutFn =
+    unsafe extern fn(context: *mut ffi::cubeb, layout: *mut ffi::cubeb_channel_layout) -> c_int;
+pub type EnumerateDevicesFn =
+    unsafe extern fn(context: *mut ffi::cubeb, devtype: ffi::cubeb_device_type,
+                     collection: *mut ffi::cubeb_device_collection) -> c_int;
+pub type DeviceCollectionDestroyFn =
+    unsafe extern fn(context: *mut ffi::cubeb,
+                     collection: *mut ffi::cubeb_device_collection) -> c_int;
+pub type DestroyFn =
+    unsafe extern "C" fn(context: *mut ffi::cubeb);
+pub type StreamInitFn =
+    unsafe extern fn(context: *mut ffi::cubeb,
+                     stream: *mut *mut ffi::cubeb_stream,
+                     stream_name: *const c_char,
+                     input_device: ffi::cubeb_devid,
+                     input_stream_params: *const ffi::cubeb_stream_params,
+                     output_device: ffi::cubeb_devid,
+                     output_stream_params: *const ffi::cubeb_stream_params,
+                     latency: u32,
+                     data_callback: ffi::cubeb_data_callback,
+                     state_callback: ffi::cubeb_state_callback,
+                     user_ptr: *mut c_void) -> c_int;
+pub type StreamDestroyFn =
+    unsafe extern "C" fn(stream: *mut ffi::cubeb_stream);
+pub type StreamStartFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream) -> c_int;
+pub type StreamStopFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream) -> c_int;
+pub type StreamResetDefaultDeviceFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream) -> c_int;
+pub type StreamGetPositionFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream, position: *mut u64) -> c_int;
+pub type StreamGetLatencyFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream, latency: *mut u32) -> c_int;
+pub type StreamSetVolumeFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream, volumes: f32) -> c_int;
+pub type StreamSetPanningFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream, panning: f32) -> c_int;
+pub type StreamGetCurrentDeviceFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream,
+                     device: *mut *const ffi::cubeb_device) -> c_int;
+pub type StreamDeviceDestroyFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream,
+                     device: *const ffi::cubeb_device) -> c_int;
+pub type StreamRegisterDeviceChangedCallbackFn =
+    unsafe extern fn(stream: *mut ffi::cubeb_stream,
+                     device_changed_callback: ffi::cubeb_device_changed_callback) -> c_int;
+pub type RegisterDeviceCollectionChangedFn =
+    unsafe extern fn(context: *mut ffi::cubeb,
+                     devtype: ffi::cubeb_device_type,
+                     callback: ffi::cubeb_device_collection_changed_callback,
+                     user_ptr: *mut c_void) -> c_int;
+
 #[repr(C)]
 pub struct Ops {
-    pub init: Option<
-        unsafe extern fn(context: *mut *mut ffi::cubeb,
-                         context_name: *const c_char)
-                         -> c_int>,
-    pub get_backend_id: Option<
-        unsafe extern fn(context: *mut ffi::cubeb) -> *const c_char>,
-    pub get_max_channel_count: Option<
-        unsafe extern fn(context: *mut ffi::cubeb,
-                         max_channels: *mut u32)
-                         -> c_int>,
-    pub get_min_latency: Option<
-        unsafe extern fn(context: *mut ffi::cubeb,
-                         params: ffi::cubeb_stream_params,
-                         latency_ms: *mut u32)
-                         -> c_int>,
+    pub init: Option<InitFn>,
+    pub get_backend_id: Option<GetBackendIdFn>,
+    pub get_max_channel_count: Option<GetMaxChannelCountFn>,
+    pub get_min_latency: Option<GetMinLatencyFn>,
     pub get_preferred_sample_rate: Option<
         unsafe extern fn(context: *mut ffi::cubeb, rate: *mut u32) -> c_int>,
     pub get_preferred_channel_layout: Option<
@@ -70,19 +124,7 @@ pub struct Ops {
                          collection: *mut ffi::cubeb_device_collection)
                          -> c_int>,
     pub destroy: Option<unsafe extern "C" fn(context: *mut ffi::cubeb)>,
-    pub stream_init: Option<
-        unsafe extern fn(context: *mut ffi::cubeb,
-                         stream: *mut *mut ffi::cubeb_stream,
-                         stream_name: *const c_char,
-                         input_device: ffi::cubeb_devid,
-                         input_stream_params: *const ffi::cubeb_stream_params,
-                         output_device: ffi::cubeb_devid,
-                         output_stream_params: *const ffi::cubeb_stream_params,
-                         latency: u32,
-                         data_callback: ffi::cubeb_data_callback,
-                         state_callback: ffi::cubeb_state_callback,
-                         user_ptr: *mut c_void)
-                         -> c_int>,
+    pub stream_init: Option<StreamInitFn>,
     pub stream_destroy: Option<unsafe extern "C" fn(stream: *mut ffi::cubeb_stream)>,
     pub stream_start: Option<
         unsafe extern fn(stream: *mut ffi::cubeb_stream) -> c_int>,
@@ -118,11 +160,7 @@ pub struct Ops {
                          ffi::cubeb_device_changed_callback)
                          -> c_int>,
     pub register_device_collection_changed: Option<
-        unsafe extern fn(context: *mut ffi::cubeb,
-                         devtype: ffi::cubeb_device_type,
-                         callback: ffi::cubeb_device_collection_changed_callback,
-                         user_ptr: *mut c_void)
-                             -> c_int>
+            RegisterDeviceCollectionChangedFn>
 }
 
 #[repr(C)]
@@ -154,20 +192,12 @@ cubeb_enum! {
 }
 
 #[repr(C)]
-#[derive(Copy)]
+#[derive(Clone, Copy)]
 pub struct cubeb_channel_map {
     pub channels: c_uint,
     pub map: [cubeb_channel; CHANNEL_MAX as usize]
 }
 
-impl Clone for cubeb_channel_map {
-    /// Returns a deep copy of the value.
-    #[inline]
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-
 impl Debug for cubeb_channel_map {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         fmt.debug_struct("cubeb_channel_map")
diff --git a/media/cubeb-rs/cubeb-backend/src/traits.rs b/media/cubeb-rs/cubeb-backend/src/traits.rs
index 6059ce4db0f4..eb6674bb5849 100644
--- a/media/cubeb-rs/cubeb-backend/src/traits.rs
+++ b/media/cubeb-rs/cubeb-backend/src/traits.rs
@@ -23,6 +23,7 @@ pub trait Context {
         &self,
         collection: *mut ffi::cubeb_device_collection,
     );
+    #[cfg_attr(feature = "cargo-clippy", allow(too_many_arguments))]
     fn stream_init(
         &self,
         stream_name: Option<&CStr>,
diff --git a/media/cubeb-rs/cubeb-core/src/error.rs b/media/cubeb-rs/cubeb-core/src/error.rs
index 154eeadd7c22..5d8afbbab0b7 100644
--- a/media/cubeb-rs/cubeb-core/src/error.rs
+++ b/media/cubeb-rs/cubeb-core/src/error.rs
@@ -18,11 +18,11 @@ impl Error {
 
     pub unsafe fn from_raw(code: ffi::cubeb_error_code) -> Error {
         let code = match code {
-            ffi::CUBEB_ERROR => ErrorCode::Error,
             ffi::CUBEB_ERROR_INVALID_FORMAT => ErrorCode::InvalidFormat,
             ffi::CUBEB_ERROR_INVALID_PARAMETER => ErrorCode::InvalidParameter,
             ffi::CUBEB_ERROR_NOT_SUPPORTED => ErrorCode::NotSupported,
             ffi::CUBEB_ERROR_DEVICE_UNAVAILABLE => ErrorCode::DeviceUnavailable,
+            // Everything else is just the generic error
             _ => ErrorCode::Error,
         };
 
diff --git a/media/cubeb-rs/cubeb-core/src/ffi.rs b/media/cubeb-rs/cubeb-core/src/ffi.rs
index a7b4bf90b6ce..18ccf2135311 100644
--- a/media/cubeb-rs/cubeb-core/src/ffi.rs
+++ b/media/cubeb-rs/cubeb-core/src/ffi.rs
@@ -87,13 +87,21 @@ cubeb_enum! {
     }
 }
 
+cubeb_enum! {
+    pub enum cubeb_stream_prefs: c_int {
+        CUBEB_STREAM_PREF_NONE     = 0x00,
+        CUBEB_STREAM_PREF_LOOPBACK = 0x01,
+    }
+}
+
 #[repr(C)]
 #[derive(Clone, Copy, Debug)]
 pub struct cubeb_stream_params {
     pub format: cubeb_sample_format,
     pub rate: c_uint,
     pub channels: c_uint,
-    pub layout: cubeb_channel_layout
+    pub layout: cubeb_channel_layout,
+    pub prefs: cubeb_stream_prefs
 }
 
 #[repr(C)]
@@ -222,7 +230,7 @@ mod test {
         use super::cubeb_stream_params;
         assert_eq!(
             size_of::<cubeb_stream_params>(),
-            16usize,
+            20usize,
             concat!("Size of: ", stringify!(cubeb_stream_params))
         );
         assert_eq!(
@@ -270,6 +278,16 @@ mod test {
                 stringify!(layout)
             )
         );
+        assert_eq!(
+            unsafe { &(*(0 as *const cubeb_stream_params)).prefs as *const _ as usize },
+            16usize,
+            concat!(
+                "Alignment of field: ",
+                stringify!(cubeb_stream_params),
+                "::",
+                stringify!(prefs)
+            )
+        );
     }
 
     #[test]
diff --git a/media/cubeb-rs/cubeb-core/src/lib.rs b/media/cubeb-rs/cubeb-core/src/lib.rs
index 86b7f510cc32..af6903cfa557 100644
--- a/media/cubeb-rs/cubeb-core/src/lib.rs
+++ b/media/cubeb-rs/cubeb-core/src/lib.rs
@@ -145,7 +145,6 @@ pub enum ChannelLayout {
 impl From<ffi::cubeb_channel_layout> for ChannelLayout {
     fn from(x: ffi::cubeb_channel_layout) -> ChannelLayout {
         match x {
-            ffi::CUBEB_LAYOUT_UNDEFINED => ChannelLayout::Undefined,
             ffi::CUBEB_LAYOUT_DUAL_MONO => ChannelLayout::DualMono,
             ffi::CUBEB_LAYOUT_DUAL_MONO_LFE => ChannelLayout::DualMonoLfe,
             ffi::CUBEB_LAYOUT_MONO => ChannelLayout::Mono,
@@ -165,11 +164,20 @@ impl From<ffi::cubeb_channel_layout> for ChannelLayout {
             ffi::CUBEB_LAYOUT_3F3R_LFE => ChannelLayout::Layout3F3RLfe,
             ffi::CUBEB_LAYOUT_3F4_LFE => ChannelLayout::Layout3F4Lfe,
             // TODO: Implement TryFrom
+            // Everything else is just undefined.
             _ => ChannelLayout::Undefined,
         }
     }
 }
 
+/// Miscellaneous stream preferences.
+bitflags! {
+    pub struct StreamPrefs: ffi::cubeb_stream_prefs {
+        const STREAM_PREF_NONE = ffi::CUBEB_STREAM_PREF_NONE;
+        const STREAM_PREF_LOOPBACK = ffi::CUBEB_STREAM_PREF_LOOPBACK;
+    }
+}
+
 /// Stream format initialization parameters.
 #[derive(Clone, Copy)]
 pub struct StreamParams {
@@ -233,6 +241,10 @@ impl StreamParams {
                CUBEB_LAYOUT_3F3R_LFE => Layout3F3RLfe,
                CUBEB_LAYOUT_3F4_LFE => Layout3F4Lfe)
     }
+
+    pub fn prefs(&self) -> StreamPrefs {
+        StreamPrefs::from_bits(self.raw.prefs).unwrap()
+    }
 }
 
 impl Binding for StreamParams {
@@ -292,7 +304,7 @@ impl<'a> Binding for Device<'a> {
     }
 }
 
-/// Stream states signaled via state_callback.
+/// Stream states signaled via `state_callback`.
 #[derive(PartialEq, Eq, Clone, Debug, Copy)]
 pub enum State {
     /// Stream started.
@@ -594,4 +606,12 @@ mod tests {
         assert_eq!(params.rate(), 44100);
     }
 
+    #[test]
+    fn stream_params_raw_prefs() {
+        use STREAM_PREF_LOOPBACK;
+        let mut raw: super::ffi::cubeb_stream_params = unsafe { mem::zeroed() };
+        raw.prefs = STREAM_PREF_LOOPBACK.bits();
+        let params = unsafe { super::StreamParams::from_raw(&raw as *const _) };
+        assert_eq!(params.prefs(), STREAM_PREF_LOOPBACK);
+    }
 }
diff --git a/media/libcubeb/README_MOZILLA b/media/libcubeb/README_MOZILLA
index fafdcd4c968e..1e3e0ad1e230 100644
--- a/media/libcubeb/README_MOZILLA
+++ b/media/libcubeb/README_MOZILLA
@@ -1,12 +1,8 @@
 The source from this directory was copied from the cubeb 
 git repository using the update.sh script.  The only changes
-made were those applied by update.sh, the addition of
-Makefile.in build files for the Mozilla build system,
-and the following patches, which may be overwritten when
-included upstream.
-https://github.com/kinetiknz/cubeb/pull/398/commits/c8e66dee61a35e6a6d54e3630e1668bdbd6984b4
-https://github.com/kinetiknz/cubeb/pull/398/commits/2ed979bc891cf1a7822799947a357d4d3b625964
+made were those applied by update.sh and the addition of
+Makefile.in build files for the Mozilla build system.
 
 The cubeb git repository is: git://github.com/kinetiknz/cubeb.git
 
-The git commit ID used was 2b98e3d3279322ce0764ae2b9f28a9ea9000418b (2018-01-19 10:17:28 +1300)
+The git commit ID used was 4c18a84a4573a23a1c39ccf6c70f1a6c328cb110 (2018-01-23 08:50:28 +1300)
diff --git a/media/libcubeb/cubeb-pulse-rs/README_MOZILLA b/media/libcubeb/cubeb-pulse-rs/README_MOZILLA
index e20f28323bd3..9da689be69df 100644
--- a/media/libcubeb/cubeb-pulse-rs/README_MOZILLA
+++ b/media/libcubeb/cubeb-pulse-rs/README_MOZILLA
@@ -5,4 +5,4 @@ Makefile.in build files for the Mozilla build system.
 
 The cubeb-pulse-rs git repository is: https://github.com/djg/cubeb-pulse-rs.git
 
-The git commit ID used was cb7141e3aae5471b3a8ac1e4524f35d04edcdf4e (2018-01-17 13:10:58 +1000)
+The git commit ID used was deadde7d14e0010628471e33a538a0a1e59765ff (2018-01-25 10:00:16 +1000)
diff --git a/media/libcubeb/cubeb-pulse-rs/cubeb-ffi/src/ffi.rs b/media/libcubeb/cubeb-pulse-rs/cubeb-ffi/src/ffi.rs
index 266082563ec9..e2c668b0a8cf 100644
--- a/media/libcubeb/cubeb-pulse-rs/cubeb-ffi/src/ffi.rs
+++ b/media/libcubeb/cubeb-pulse-rs/cubeb-ffi/src/ffi.rs
@@ -51,6 +51,16 @@ pub const LAYOUT_3F3R_LFE: ChannelLayout = 17;
 pub const LAYOUT_3F4_LFE: ChannelLayout = 18;
 pub const LAYOUT_MAX: ChannelLayout = 256;
 
+
+// These need to match cubeb_device_type
+bitflags! {
+    #[repr(C)]
+    pub struct StreamPrefs : u32 {
+        const STREAM_PREF_NONE = 0x00;
+        const STREAM_PREF_LOOPBACK = 0x01;
+    }
+}
+
 #[repr(C)]
 #[derive(Clone, Copy, Debug)]
 pub struct StreamParams {
@@ -58,6 +68,7 @@ pub struct StreamParams {
     pub rate: u32,
     pub channels: u32,
     pub layout: ChannelLayout,
+    pub prefs: StreamPrefs,
 }
 
 #[repr(C)]
@@ -308,7 +319,7 @@ extern "C" {
 #[test]
 fn bindgen_test_layout_stream_params() {
     assert_eq!(::std::mem::size_of::<StreamParams>(),
-               16usize,
+               20usize,
                concat!("Size of: ", stringify!(StreamParams)));
     assert_eq!(::std::mem::align_of::<StreamParams>(),
                4usize,
@@ -337,6 +348,12 @@ fn bindgen_test_layout_stream_params() {
                        stringify!(StreamParams),
                        "::",
                        stringify!(layout)));
+    assert_eq!(unsafe { &(*(0 as *const StreamParams)).prefs as *const _ as usize },
+               16usize,
+               concat!("Alignment of field: ",
+                       stringify!(StreamParams),
+                       "::",
+                       stringify!(layout)));
 }
 
 #[test]
diff --git a/media/libcubeb/cubeb-pulse-rs/pulse-rs/src/lib.rs b/media/libcubeb/cubeb-pulse-rs/pulse-rs/src/lib.rs
index ac6e7127ab36..f12f0a5bfb35 100644
--- a/media/libcubeb/cubeb-pulse-rs/pulse-rs/src/lib.rs
+++ b/media/libcubeb/cubeb-pulse-rs/pulse-rs/src/lib.rs
@@ -370,7 +370,7 @@ impl SubscriptionEvent {
     }
 
     pub fn event_type(self) -> SubscriptionEventType {
-        unsafe { ::std::mem::transmute(((self.0 & ffi::PA_SUBSCRIPTION_EVENT_TYPE_MASK) >> 4)) }
+        unsafe { ::std::mem::transmute((self.0 & ffi::PA_SUBSCRIPTION_EVENT_TYPE_MASK) >> 4) }
     }
 }
 
diff --git a/media/libcubeb/cubeb-pulse-rs/src/backend/context.rs b/media/libcubeb/cubeb-pulse-rs/src/backend/context.rs
index 03e36091932e..f5d19f379907 100644
--- a/media/libcubeb/cubeb-pulse-rs/src/backend/context.rs
+++ b/media/libcubeb/cubeb-pulse-rs/src/backend/context.rs
@@ -37,7 +37,7 @@ fn pa_channel_to_cubeb_channel(channel: pulse::ChannelPosition) -> cubeb::Channe
 fn channel_map_to_layout(cm: &pulse::ChannelMap) -> cubeb::ChannelLayout {
     use pulse::ChannelPosition;
     let mut cubeb_map: cubeb::ChannelMap = Default::default();
-    cubeb_map.channels = cm.channels as u32;
+    cubeb_map.channels = u32::from(cm.channels);
     for i in 0usize..cm.channels as usize {
         cubeb_map.map[i] = pa_channel_to_cubeb_channel(ChannelPosition::try_from(cm.map[i])
                                                            .unwrap_or(ChannelPosition::Invalid));
@@ -176,6 +176,7 @@ impl Context {
         }
     }
 
+    #[cfg_attr(feature = "cargo-clippy", allow(too_many_arguments))]
     pub fn new_stream(&mut self,
                       stream_name: &CStr,
                       input_device: cubeb::DeviceId,
@@ -205,7 +206,7 @@ impl Context {
 
     pub fn max_channel_count(&self) -> Result<u32> {
         match self.default_sink_info {
-            Some(ref info) => Ok(info.channel_map.channels as u32),
+            Some(ref info) => Ok(u32::from(info.channel_map.channels)),
             None => Err(cubeb::ERROR),
         }
     }
@@ -276,7 +277,7 @@ impl Context {
                 preferred: preferred,
                 format: cubeb::DeviceFmt::all(),
                 default_format: pulse_format_to_cubeb_format(info.sample_spec.format),
-                max_channels: info.channel_map.channels as u32,
+                max_channels: u32::from(info.channel_map.channels),
                 min_rate: 1,
                 max_rate: PA_RATE_MAX,
                 default_rate: info.sample_spec.rate,
@@ -332,7 +333,7 @@ impl Context {
                 preferred: preferred,
                 format: cubeb::DeviceFmt::all(),
                 default_format: pulse_format_to_cubeb_format(info.sample_spec.format),
-                max_channels: info.channel_map.channels as u32,
+                max_channels: u32::from(info.channel_map.channels),
                 min_rate: 1,
                 max_rate: PA_RATE_MAX,
                 default_rate: info.sample_spec.rate,
@@ -341,7 +342,6 @@ impl Context {
             };
 
             list_data.devinfo.push(devinfo);
-
         }
 
         fn default_device_names(_: &pulse::Context, info: &pulse::ServerInfo, user_data: *mut c_void) {
@@ -403,7 +403,7 @@ impl Context {
             let mut devices = Vec::from_raw_parts(coll.device as *mut cubeb::DeviceInfo,
                                                   coll.count,
                                                   coll.count);
-            for dev in devices.iter_mut() {
+            for dev in &mut devices {
                 if !dev.group_id.is_null() {
                     let _ = CString::from_raw(dev.group_id as *mut _);
                 }
@@ -558,18 +558,15 @@ impl Context {
         }
 
         let context_ptr: *mut c_void = self as *mut _ as *mut _;
-        match self.context.take() {
-            Some(ctx) => {
-                self.mainloop.lock();
-                if let Ok(o) = ctx.drain(drain_complete, context_ptr) {
-                    self.operation_wait(None, &o);
-                }
-                ctx.clear_state_callback();
-                ctx.disconnect();
-                ctx.unref();
-                self.mainloop.unlock();
-            },
-            _ => {},
+        if let Some(ctx) = self.context.take() {
+            self.mainloop.lock();
+            if let Ok(o) = ctx.drain(drain_complete, context_ptr) {
+                self.operation_wait(None, &o);
+            }
+            ctx.clear_state_callback();
+            ctx.disconnect();
+            ctx.unref();
+            self.mainloop.unlock();
         }
     }
 
diff --git a/media/libcubeb/cubeb-pulse-rs/src/backend/stream.rs b/media/libcubeb/cubeb-pulse-rs/src/backend/stream.rs
index a0e41058058a..cd8de53f7d51 100644
--- a/media/libcubeb/cubeb-pulse-rs/src/backend/stream.rs
+++ b/media/libcubeb/cubeb-pulse-rs/src/backend/stream.rs
@@ -34,7 +34,7 @@ fn cubeb_channel_to_pa_channel(channel: cubeb::Channel) -> pa_channel_position_t
         PA_CHANNEL_POSITION_LFE           // CHANNEL_LFE
     ];
 
-    let idx: i32 = channel.into();
+    let idx: i32 = channel;
     MAP[idx as usize]
 }
 
@@ -89,6 +89,7 @@ impl<'ctx> Drop for Stream<'ctx> {
 }
 
 impl<'ctx> Stream<'ctx> {
+    #[cfg_attr(feature = "cargo-clippy", allow(too_many_arguments))]
     pub fn new(context: &'ctx Context,
                stream_name: &CStr,
                input_device: cubeb::DeviceId,
@@ -114,10 +115,8 @@ impl<'ctx> Stream<'ctx> {
                 let readable_size: i32 = s.readable_size()
                     .and_then(|s| Ok(s as i32))
                     .unwrap_or(-1);
-                if readable_size > 0 {
-                    if unsafe { s.peek(buffer, size).is_err() } {
-                        return -1;
-                    }
+                if readable_size > 0 && unsafe { s.peek(buffer, size).is_err() } {
+                    return -1;
                 }
                 readable_size
             }
@@ -230,7 +229,6 @@ impl<'ctx> Stream<'ctx> {
                         return Err(e);
                     },
                 }
-
             }
 
             // Set up input stream
@@ -258,7 +256,6 @@ impl<'ctx> Stream<'ctx> {
                         return Err(e);
                     },
                 }
-
             }
 
             let r = if stm.wait_until_ready() {
@@ -309,31 +306,25 @@ impl<'ctx> Stream<'ctx> {
 
         self.context.mainloop.lock();
         {
-            match self.output_stream.take() {
-                Some(stm) => {
-                    if !self.drain_timer.is_null() {
-                        /* there's no pa_rttime_free, so use this instead. */
-                        self.context
-                            .mainloop
-                            .get_api()
-                            .time_free(self.drain_timer);
-                    }
-                    stm.clear_state_callback();
-                    stm.clear_write_callback();
-                    let _ = stm.disconnect();
-                    stm.unref();
-                },
-                _ => {},
+            if let Some(stm) = self.output_stream.take() {
+                if !self.drain_timer.is_null() {
+                    /* there's no pa_rttime_free, so use this instead. */
+                    self.context
+                        .mainloop
+                        .get_api()
+                        .time_free(self.drain_timer);
+                }
+                stm.clear_state_callback();
+                stm.clear_write_callback();
+                let _ = stm.disconnect();
+                stm.unref();
             }
 
-            match self.input_stream.take() {
-                Some(stm) => {
-                    stm.clear_state_callback();
-                    stm.clear_read_callback();
-                    let _ = stm.disconnect();
-                    stm.unref();
-                },
-                _ => {},
+            if let Some(stm) = self.input_stream.take() {
+                stm.clear_state_callback();
+                stm.clear_read_callback();
+                let _ = stm.disconnect();
+                stm.unref();
             }
         }
         self.context.mainloop.unlock();
@@ -416,7 +407,7 @@ impl<'ctx> Stream<'ctx> {
             Some(ref stm) => {
                 match stm.get_latency() {
                     Ok(StreamLatency::Positive(r_usec)) => {
-                        let latency = (r_usec * self.output_sample_spec.rate as pa_usec_t / PA_USEC_PER_SEC) as u32;
+                        let latency = (r_usec * pa_usec_t::from(self.output_sample_spec.rate) / PA_USEC_PER_SEC) as u32;
                         Ok(latency)
                     },
                     Ok(_) => {
@@ -451,8 +442,8 @@ impl<'ctx> Stream<'ctx> {
                         self.volume = volume;
                     } else {
                         let channels = stm.get_sample_spec().channels;
-                        let vol = pulse::sw_volume_from_linear(volume as f64);
-                        cvol.set(channels as u32, vol);
+                        let vol = pulse::sw_volume_from_linear(f64::from(volume));
+                        cvol.set(u32::from(channels), vol);
 
                         let index = stm.get_index();
 
@@ -564,6 +555,10 @@ impl<'ctx> Stream<'ctx> {
                    stream_name: &CStr)
                    -> Result<pulse::Stream> {
 
+        if stream_params.prefs == cubeb::StreamPrefs::STREAM_PREF_LOOPBACK {
+            return Err(cubeb::ERROR_NOT_SUPPORTED);
+        }
+
         fn to_pulse_format(format: cubeb::SampleFormat) -> pulse::SampleFormat {
             match format {
                 cubeb::SAMPLE_S16LE => pulse::SampleFormat::Signed16LE,
@@ -689,6 +684,7 @@ impl<'ctx> Stream<'ctx> {
         true
     }
 
+    #[cfg_attr(feature = "cargo-clippy", allow(cyclomatic_complexity))]
     fn trigger_user_callback(&mut self, input_data: *const c_void, nbytes: usize) {
         fn drained_cb(a: &pulse::MainloopApi, e: *mut pa_time_event, _tv: &pulse::TimeVal, u: *mut c_void) {
             let stm = unsafe { &mut *(u as *mut Stream) };
diff --git a/media/libcubeb/gtest/test_audio.cpp b/media/libcubeb/gtest/test_audio.cpp
index 5548b34ab5bd..df513669517d 100644
--- a/media/libcubeb/gtest/test_audio.cpp
+++ b/media/libcubeb/gtest/test_audio.cpp
@@ -123,6 +123,7 @@ int run_test(int num_channels, layout_info layout, int sampling_rate, int is_flo
   params.rate = sampling_rate;
   params.channels = num_channels;
   params.layout = layout.layout;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   synth_state synth(params.channels, params.rate);
 
@@ -171,6 +172,7 @@ int run_panning_volume_test(int is_float)
   params.rate = 44100;
   params.channels = 2;
   params.layout = CUBEB_LAYOUT_STEREO;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   synth_state synth(params.channels, params.rate);
 
diff --git a/media/libcubeb/gtest/test_devices.cpp b/media/libcubeb/gtest/test_devices.cpp
index 93c869248399..10c14c3f74f5 100644
--- a/media/libcubeb/gtest/test_devices.cpp
+++ b/media/libcubeb/gtest/test_devices.cpp
@@ -190,6 +190,7 @@ TEST(cubeb, enumerate_devices)
   input_params.rate = output_params.rate = 48000;
   input_params.channels = output_params.channels = 1;
   input_params.layout = output_params.layout = CUBEB_LAYOUT_MONO;
+  input_params.prefs = output_params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "Cubeb duplex",
                         NULL, &input_params, NULL, &output_params,
diff --git a/media/libcubeb/gtest/test_duplex.cpp b/media/libcubeb/gtest/test_duplex.cpp
index 427b503929a7..09315ba4b5c5 100644
--- a/media/libcubeb/gtest/test_duplex.cpp
+++ b/media/libcubeb/gtest/test_duplex.cpp
@@ -101,10 +101,12 @@ TEST(cubeb, duplex)
   input_params.rate = 48000;
   input_params.channels = 1;
   input_params.layout = CUBEB_LAYOUT_MONO;
+  input_params.prefs = CUBEB_STREAM_PREF_NONE;
   output_params.format = STREAM_FORMAT;
   output_params.rate = 48000;
   output_params.channels = 2;
   output_params.layout = CUBEB_LAYOUT_STEREO;
+  output_params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_get_min_latency(ctx, &output_params, &latency_frames);
   ASSERT_EQ(r, CUBEB_OK) << "Could not get minimal latency";
diff --git a/media/libcubeb/gtest/test_latency.cpp b/media/libcubeb/gtest/test_latency.cpp
index 6af39d598875..f4aa6b07c8da 100644
--- a/media/libcubeb/gtest/test_latency.cpp
+++ b/media/libcubeb/gtest/test_latency.cpp
@@ -34,7 +34,8 @@ TEST(cubeb, latency)
     CUBEB_SAMPLE_FLOAT32NE,
     preferred_rate,
     max_channels,
-    CUBEB_LAYOUT_UNDEFINED
+    CUBEB_LAYOUT_UNDEFINED,
+    CUBEB_STREAM_PREF_NONE
   };
   r = cubeb_get_min_latency(ctx, &params, &latency_frames);
   ASSERT_TRUE(r == CUBEB_OK || r == CUBEB_ERROR_NOT_SUPPORTED);
diff --git a/media/libcubeb/gtest/test_loopback.cpp b/media/libcubeb/gtest/test_loopback.cpp
new file mode 100644
index 000000000000..4fe513708fa6
--- /dev/null
+++ b/media/libcubeb/gtest/test_loopback.cpp
@@ -0,0 +1,575 @@
+/*
+ * Copyright © 2017 Mozilla Foundation
+ *
+ * This program is made available under an ISC-style license.  See the
+ * accompanying file LICENSE for details.
+ */
+
+ /* libcubeb api/function test. Requests a loopback device and checks that
+    output is being looped back to input. NOTE: Usage of output devices while
+    performing this test will cause flakey results! */
+#include "gtest/gtest.h"
+#if !defined(_XOPEN_SOURCE)
+#define _XOPEN_SOURCE 600
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <algorithm>
+#include <memory>
+#include <mutex>
+#include <string>
+#include "cubeb/cubeb.h"
+#include "common.h"
+
+const uint32_t SAMPLE_FREQUENCY = 48000;
+const uint32_t TONE_FREQUENCY = 440;
+const double OUTPUT_AMPLITUDE = 0.25;
+const uint32_t NUM_FRAMES_TO_OUTPUT = SAMPLE_FREQUENCY / 20; /* play ~50ms of samples */
+
+template<typename T> T ConvertSampleToOutput(double input);
+template<> float ConvertSampleToOutput(double input) { return float(input); }
+template<> short ConvertSampleToOutput(double input) { return short(input * 32767.0f); }
+
+template<typename T> double ConvertSampleFromOutput(T sample);
+template<> double ConvertSampleFromOutput(float sample) { return double(sample); }
+template<> double ConvertSampleFromOutput(short sample) { return double(sample / 32767.0); }
+
+/* Simple cross correlation to help find phase shift. Not a performant impl */
+std::vector<double> cross_correlate(std::vector<double> & f,
+                                    std::vector<double> & g,
+                                    size_t signal_length)
+{
+  /* the length we sweep our window through to find the cross correlation */
+  size_t sweep_length = f.size() - signal_length + 1;
+  std::vector<double> correlation;
+  correlation.reserve(sweep_length);
+  for (size_t i = 0; i < sweep_length; i++) {
+    double accumulator = 0.0;
+    for (size_t j = 0; j < signal_length; j++) {
+      accumulator += f.at(j) * g.at(i + j);
+    }
+    correlation.push_back(accumulator);
+  }
+  return correlation;
+}
+
+/* best effort discovery of phase shift between output and (looped) input*/
+size_t find_phase(std::vector<double> & output_frames,
+                  std::vector<double> & input_frames,
+                  size_t signal_length)
+{
+  std::vector<double> correlation = cross_correlate(output_frames, input_frames, signal_length);
+  size_t phase = 0;
+  double max_correlation = correlation.at(0);
+  for (size_t i = 1; i < correlation.size(); i++) {
+    if (correlation.at(i) > max_correlation) {
+      max_correlation = correlation.at(i);
+      phase = i;
+    }
+  }
+  return phase;
+}
+
+std::vector<double> normalize_frames(std::vector<double> & frames) {
+  double max = abs(*std::max_element(frames.begin(), frames.end(),
+                                     [](double a, double b) { return abs(a) < abs(b); }));
+  std::vector<double> normalized_frames;
+  normalized_frames.reserve(frames.size());
+  for (const double frame : frames) {
+    normalized_frames.push_back(frame / max);
+  }
+  return normalized_frames;
+}
+
+/* heuristic comparison of aligned output and input signals, gets flaky if TONE_FREQUENCY is too high */
+void compare_signals(std::vector<double> & output_frames,
+                     std::vector<double> & input_frames)
+{
+  ASSERT_EQ(output_frames.size(), input_frames.size()) << "#Output frames != #input frames";
+  size_t num_frames = output_frames.size();
+  std::vector<double> normalized_output_frames = normalize_frames(output_frames);
+  std::vector<double> normalized_input_frames = normalize_frames(input_frames);
+
+  /* calculate mean absolute errors */
+  /* mean absolute errors between output and input */
+  double io_mas = 0.0;
+  /* mean absolute errors between output and silence */
+  double output_silence_mas = 0.0;
+  /* mean absolute errors between input and silence */
+  double input_silence_mas = 0.0;
+  for (size_t i = 0; i < num_frames; i++) {
+    io_mas += abs(normalized_output_frames.at(i) - normalized_input_frames.at(i));
+    output_silence_mas += abs(normalized_output_frames.at(i));
+    input_silence_mas += abs(normalized_input_frames.at(i));
+  }
+  io_mas /= num_frames;
+  output_silence_mas /= num_frames;
+  input_silence_mas /= num_frames;
+
+  ASSERT_LT(io_mas, output_silence_mas)
+    << "Error between output and input should be less than output and silence!";
+  ASSERT_LT(io_mas, input_silence_mas)
+    << "Error between output and input should be less than output and silence!";
+
+  /* make sure extrema are in (roughly) correct location */
+  /* number of maxima + minama expected in the frames*/
+  const long NUM_EXTREMA = 2 * TONE_FREQUENCY * NUM_FRAMES_TO_OUTPUT / SAMPLE_FREQUENCY;
+  /* expected index of first maxima */
+  const long FIRST_MAXIMUM_INDEX = SAMPLE_FREQUENCY / TONE_FREQUENCY / 4;
+  /* Threshold we expect all maxima and minima to be above or below. Ideally
+     the extrema would be 1 or -1, but particularly at the start of loopback
+     the values seen can be significantly lower. */
+  const double THRESHOLD = 0.5;
+
+  for (size_t i = 0; i < NUM_EXTREMA; i++) {
+    bool is_maximum = i % 2 == 0;
+    /* expected offset to current extreme: i * stide between extrema */
+    size_t offset = i * SAMPLE_FREQUENCY / TONE_FREQUENCY / 2;
+    if (is_maximum) {
+      ASSERT_GT(normalized_output_frames.at(FIRST_MAXIMUM_INDEX + offset), THRESHOLD)
+        << "Output frames have unexpected missing maximum!";
+      ASSERT_GT(normalized_input_frames.at(FIRST_MAXIMUM_INDEX + offset), THRESHOLD)
+        << "Input frames have unexpected missing maximum!";
+    } else {
+      ASSERT_LT(normalized_output_frames.at(FIRST_MAXIMUM_INDEX + offset), -THRESHOLD)
+        << "Output frames have unexpected missing minimum!";
+      ASSERT_LT(normalized_input_frames.at(FIRST_MAXIMUM_INDEX + offset), -THRESHOLD)
+        << "Input frames have unexpected missing minimum!";
+    }
+  }
+}
+
+struct user_state_loopback {
+  std::mutex user_state_mutex;
+  long position = 0;
+  /* track output */
+  std::vector<double> output_frames;
+  /* track input */
+  std::vector<double> input_frames;
+};
+
+template<typename T>
+long data_cb_loop_duplex(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
+{
+  struct user_state_loopback * u = (struct user_state_loopback *) user;
+  T * ib = (T *) inputbuffer;
+  T * ob = (T *) outputbuffer;
+
+  if (stream == NULL || inputbuffer == NULL || outputbuffer == NULL) {
+    return CUBEB_ERROR;
+  }
+
+  std::lock_guard<std::mutex> lock(u->user_state_mutex);
+  /* generate our test tone on the fly */
+  for (int i = 0; i < nframes; i++) {
+    double tone = 0.0;
+    if (u->position + i < NUM_FRAMES_TO_OUTPUT) {
+      /* generate sine wave */
+      tone = sin(2 * M_PI*(i + u->position) * TONE_FREQUENCY / SAMPLE_FREQUENCY);
+      tone *= OUTPUT_AMPLITUDE;
+    }
+    ob[i] = ConvertSampleToOutput<T>(tone);
+    u->output_frames.push_back(tone);
+    /* store any looped back output, may be silence */
+    u->input_frames.push_back(ConvertSampleFromOutput(ib[i]));
+  }
+
+  u->position += nframes;
+
+  return nframes;
+}
+
+template<typename T>
+long data_cb_loop_input_only(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
+{
+  struct user_state_loopback * u = (struct user_state_loopback *) user;
+  T * ib = (T *) inputbuffer;
+
+  if (outputbuffer != NULL) {
+    // Can't assert as it needs to return, so expect to fail instead
+    EXPECT_EQ(outputbuffer, (void *) NULL) << "outputbuffer should be null in input only callback";
+    return CUBEB_ERROR;
+  }
+
+  if (stream == NULL || inputbuffer == NULL) {
+    return CUBEB_ERROR;
+  }
+
+  std::lock_guard<std::mutex> lock(u->user_state_mutex);
+  for (int i = 0; i < nframes; i++) {
+    u->input_frames.push_back(ConvertSampleFromOutput(ib[i]));
+  }
+
+  return nframes;
+}
+
+template<typename T>
+long data_cb_playback(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
+{
+  struct user_state_loopback * u = (struct user_state_loopback *) user;
+  T * ob = (T *) outputbuffer;
+
+  if (stream == NULL || outputbuffer == NULL) {
+    return CUBEB_ERROR;
+  }
+
+  std::lock_guard<std::mutex> lock(u->user_state_mutex);
+  /* generate our test tone on the fly */
+  for (int i = 0; i < nframes; i++) {
+    double tone = 0.0;
+    if (u->position + i < NUM_FRAMES_TO_OUTPUT) {
+      /* generate sine wave */
+      tone = sin(2 * M_PI*(i + u->position) * TONE_FREQUENCY / SAMPLE_FREQUENCY);
+      tone *= OUTPUT_AMPLITUDE;
+    }
+    ob[i] = ConvertSampleToOutput<T>(tone);
+    u->output_frames.push_back(tone);
+  }
+
+  u->position += nframes;
+
+  return nframes;
+}
+
+void state_cb_loop(cubeb_stream * stream, void * /*user*/, cubeb_state state)
+{
+  if (stream == NULL)
+    return;
+
+  switch (state) {
+  case CUBEB_STATE_STARTED:
+    fprintf(stderr, "stream started\n"); break;
+  case CUBEB_STATE_STOPPED:
+    fprintf(stderr, "stream stopped\n"); break;
+  case CUBEB_STATE_DRAINED:
+    fprintf(stderr, "stream drained\n"); break;
+  default:
+    fprintf(stderr, "unknown stream state %d\n", state);
+  }
+
+  return;
+}
+
+void run_loopback_duplex_test(bool is_float)
+{
+  cubeb * ctx;
+  cubeb_stream * stream;
+  cubeb_stream_params input_params;
+  cubeb_stream_params output_params;
+  int r;
+  uint32_t latency_frames = 0;
+
+  r = common_init(&ctx, "Cubeb loopback example: duplex stream");
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb library";
+
+  std::unique_ptr<cubeb, decltype(&cubeb_destroy)>
+    cleanup_cubeb_at_exit(ctx, cubeb_destroy);
+
+  input_params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16LE;
+  input_params.rate = SAMPLE_FREQUENCY;
+  input_params.channels = 1;
+  input_params.layout = CUBEB_LAYOUT_MONO;
+  input_params.prefs = CUBEB_STREAM_PREF_LOOPBACK;
+  output_params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16LE;
+  output_params.rate = SAMPLE_FREQUENCY;
+  output_params.channels = 1;
+  output_params.layout = CUBEB_LAYOUT_MONO;
+  output_params.prefs = CUBEB_STREAM_PREF_NONE;
+
+  std::unique_ptr<user_state_loopback> user_data(new user_state_loopback());
+  ASSERT_TRUE(!!user_data) << "Error allocating user data";
+
+  r = cubeb_get_min_latency(ctx, &output_params, &latency_frames);
+  ASSERT_EQ(r, CUBEB_OK) << "Could not get minimal latency";
+
+  /* setup a duplex stream with loopback */
+  r = cubeb_stream_init(ctx, &stream, "Cubeb loopback",
+                        NULL, &input_params, NULL, &output_params, latency_frames,
+                        is_float ? data_cb_loop_duplex<float> : data_cb_loop_duplex<short>,
+                        state_cb_loop, user_data.get());
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb stream";
+
+  std::unique_ptr<cubeb_stream, decltype(&cubeb_stream_destroy)>
+    cleanup_stream_at_exit(stream, cubeb_stream_destroy);
+
+  cubeb_stream_start(stream);
+  delay(150);
+  cubeb_stream_stop(stream);
+
+  /* access after stop should not happen, but lock just in case and to appease sanitization tools */
+  std::lock_guard<std::mutex> lock(user_data->user_state_mutex);
+  std::vector<double> & output_frames = user_data->output_frames;
+  std::vector<double> & input_frames = user_data->input_frames;
+  ASSERT_EQ(output_frames.size(), input_frames.size())
+    << "#Output frames != #input frames";
+
+  size_t phase = find_phase(user_data->output_frames, user_data->input_frames, NUM_FRAMES_TO_OUTPUT);
+
+  /* extract vectors of just the relevant signal from output and input */
+  auto output_frames_signal_start = output_frames.begin();
+  auto output_frames_signal_end = output_frames.begin() + NUM_FRAMES_TO_OUTPUT;
+  std::vector<double> trimmed_output_frames(output_frames_signal_start, output_frames_signal_end);
+  auto input_frames_signal_start = input_frames.begin() + phase;
+  auto input_frames_signal_end = input_frames.begin() + phase + NUM_FRAMES_TO_OUTPUT;
+  std::vector<double> trimmed_input_frames(input_frames_signal_start, input_frames_signal_end);
+
+  compare_signals(trimmed_output_frames, trimmed_input_frames);
+}
+
+TEST(cubeb, loopback_duplex)
+{
+  run_loopback_duplex_test(true);
+  run_loopback_duplex_test(false);
+}
+
+void run_loopback_separate_streams_test(bool is_float)
+{
+  cubeb * ctx;
+  cubeb_stream * input_stream;
+  cubeb_stream * output_stream;
+  cubeb_stream_params input_params;
+  cubeb_stream_params output_params;
+  int r;
+  uint32_t latency_frames = 0;
+
+  r = common_init(&ctx, "Cubeb loopback example: separate streams");
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb library";
+
+  std::unique_ptr<cubeb, decltype(&cubeb_destroy)>
+    cleanup_cubeb_at_exit(ctx, cubeb_destroy);
+
+  input_params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16LE;
+  input_params.rate = SAMPLE_FREQUENCY;
+  input_params.channels = 1;
+  input_params.layout = CUBEB_LAYOUT_MONO;
+  input_params.prefs = CUBEB_STREAM_PREF_LOOPBACK;
+  output_params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16LE;
+  output_params.rate = SAMPLE_FREQUENCY;
+  output_params.channels = 1;
+  output_params.layout = CUBEB_LAYOUT_MONO;
+
+  std::unique_ptr<user_state_loopback> user_data(new user_state_loopback());
+  ASSERT_TRUE(!!user_data) << "Error allocating user data";
+
+  r = cubeb_get_min_latency(ctx, &output_params, &latency_frames);
+  ASSERT_EQ(r, CUBEB_OK) << "Could not get minimal latency";
+
+  /* setup an input stream with loopback */
+  r = cubeb_stream_init(ctx, &input_stream, "Cubeb loopback input only",
+                        NULL, &input_params, NULL, NULL, latency_frames,
+                        is_float ? data_cb_loop_input_only<float> : data_cb_loop_input_only<short>,
+                        state_cb_loop, user_data.get());
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb stream";
+
+  std::unique_ptr<cubeb_stream, decltype(&cubeb_stream_destroy)>
+    cleanup_input_stream_at_exit(input_stream, cubeb_stream_destroy);
+
+  /* setup an output stream */
+  r = cubeb_stream_init(ctx, &output_stream, "Cubeb loopback output only",
+                        NULL, NULL, NULL, &output_params, latency_frames,
+                        is_float ? data_cb_playback<float> : data_cb_playback<short>,
+                        state_cb_loop, user_data.get());
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb stream";
+
+  std::unique_ptr<cubeb_stream, decltype(&cubeb_stream_destroy)>
+    cleanup_output_stream_at_exit(output_stream, cubeb_stream_destroy);
+
+  cubeb_stream_start(input_stream);
+  cubeb_stream_start(output_stream);
+  delay(150);
+  cubeb_stream_stop(output_stream);
+  cubeb_stream_stop(input_stream);
+
+  /* access after stop should not happen, but lock just in case and to appease sanitization tools */
+  std::lock_guard<std::mutex> lock(user_data->user_state_mutex);
+  std::vector<double> & output_frames = user_data->output_frames;
+  std::vector<double> & input_frames = user_data->input_frames;
+  ASSERT_LE(output_frames.size(), input_frames.size())
+    << "#Output frames should be less or equal to #input frames";
+
+  size_t phase = find_phase(user_data->output_frames, user_data->input_frames, NUM_FRAMES_TO_OUTPUT);
+
+  /* extract vectors of just the relevant signal from output and input */
+  auto output_frames_signal_start = output_frames.begin();
+  auto output_frames_signal_end = output_frames.begin() + NUM_FRAMES_TO_OUTPUT;
+  std::vector<double> trimmed_output_frames(output_frames_signal_start, output_frames_signal_end);
+  auto input_frames_signal_start = input_frames.begin() + phase;
+  auto input_frames_signal_end = input_frames.begin() + phase + NUM_FRAMES_TO_OUTPUT;
+  std::vector<double> trimmed_input_frames(input_frames_signal_start, input_frames_signal_end);
+
+  compare_signals(trimmed_output_frames, trimmed_input_frames);
+}
+
+TEST(cubeb, loopback_separate_streams)
+{
+  run_loopback_separate_streams_test(true);
+  run_loopback_separate_streams_test(false);
+}
+
+void run_loopback_silence_test(bool is_float)
+{
+  cubeb * ctx;
+  cubeb_stream * input_stream;
+  cubeb_stream_params input_params;
+  int r;
+  uint32_t latency_frames = 0;
+
+  r = common_init(&ctx, "Cubeb loopback example: record silence");
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb library";
+
+  std::unique_ptr<cubeb, decltype(&cubeb_destroy)>
+    cleanup_cubeb_at_exit(ctx, cubeb_destroy);
+
+  input_params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16LE;
+  input_params.rate = SAMPLE_FREQUENCY;
+  input_params.channels = 1;
+  input_params.layout = CUBEB_LAYOUT_MONO;
+  input_params.prefs = CUBEB_STREAM_PREF_LOOPBACK;
+
+  std::unique_ptr<user_state_loopback> user_data(new user_state_loopback());
+  ASSERT_TRUE(!!user_data) << "Error allocating user data";
+
+  r = cubeb_get_min_latency(ctx, &input_params, &latency_frames);
+  ASSERT_EQ(r, CUBEB_OK) << "Could not get minimal latency";
+
+  /* setup an input stream with loopback */
+  r = cubeb_stream_init(ctx, &input_stream, "Cubeb loopback input only",
+                        NULL, &input_params, NULL, NULL, latency_frames,
+                        is_float ? data_cb_loop_input_only<float> : data_cb_loop_input_only<short>,
+                        state_cb_loop, user_data.get());
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb stream";
+
+  std::unique_ptr<cubeb_stream, decltype(&cubeb_stream_destroy)>
+    cleanup_input_stream_at_exit(input_stream, cubeb_stream_destroy);
+
+  cubeb_stream_start(input_stream);
+  delay(50);
+  cubeb_stream_stop(input_stream);
+
+  /* access after stop should not happen, but lock just in case and to appease sanitization tools */
+  std::lock_guard<std::mutex> lock(user_data->user_state_mutex);
+  std::vector<double> & input_frames = user_data->input_frames;
+
+  /* expect to have at least ~50ms of frames */
+  ASSERT_GE(input_frames.size(), SAMPLE_FREQUENCY / 20);
+  double EPISILON = 0.000001;
+  /* frames should be 0.0, but use epsilon to avoid possible issues with impls
+  that may use ~0.0 silence values. */
+  for (double frame : input_frames) {
+    ASSERT_LT(abs(frame), EPISILON);
+  }
+}
+
+TEST(cubeb, loopback_silence)
+{
+  run_loopback_silence_test(true);
+  run_loopback_silence_test(false);
+}
+
+void run_loopback_device_selection_test(bool is_float)
+{
+  cubeb * ctx;
+  cubeb_device_collection collection;
+  cubeb_stream * input_stream;
+  cubeb_stream * output_stream;
+  cubeb_stream_params input_params;
+  cubeb_stream_params output_params;
+  int r;
+  uint32_t latency_frames = 0;
+
+  r = common_init(&ctx, "Cubeb loopback example: device selection, separate streams");
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb library";
+
+  std::unique_ptr<cubeb, decltype(&cubeb_destroy)>
+    cleanup_cubeb_at_exit(ctx, cubeb_destroy);
+
+  r = cubeb_enumerate_devices(ctx, CUBEB_DEVICE_TYPE_OUTPUT, &collection);
+  if (r == CUBEB_ERROR_NOT_SUPPORTED) {
+    fprintf(stderr, "Device enumeration not supported"
+            " for this backend, skipping this test.\n");
+    return;
+  }
+
+  ASSERT_EQ(r, CUBEB_OK) << "Error enumerating devices " << r;
+  /* get first preferred output device id */
+  std::string device_id;
+  for (size_t i = 0; i < collection.count; i++) {
+    if (collection.device[i].preferred) {
+      device_id = collection.device[i].device_id;
+      break;
+    }
+  }
+  cubeb_device_collection_destroy(ctx, &collection);
+  if (device_id.empty()) {
+    fprintf(stderr, "Could not find preferred device, aborting test.\n");
+    return;
+  }
+
+  input_params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16LE;
+  input_params.rate = SAMPLE_FREQUENCY;
+  input_params.channels = 1;
+  input_params.layout = CUBEB_LAYOUT_MONO;
+  input_params.prefs = CUBEB_STREAM_PREF_LOOPBACK;
+  output_params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16LE;
+  output_params.rate = SAMPLE_FREQUENCY;
+  output_params.channels = 1;
+  output_params.layout = CUBEB_LAYOUT_MONO;
+
+  std::unique_ptr<user_state_loopback> user_data(new user_state_loopback());
+  ASSERT_TRUE(!!user_data) << "Error allocating user data";
+
+  r = cubeb_get_min_latency(ctx, &output_params, &latency_frames);
+  ASSERT_EQ(r, CUBEB_OK) << "Could not get minimal latency";
+
+  /* setup an input stream with loopback */
+  r = cubeb_stream_init(ctx, &input_stream, "Cubeb loopback input only",
+                        device_id.c_str(), &input_params, NULL, NULL, latency_frames,
+                        is_float ? data_cb_loop_input_only<float> : data_cb_loop_input_only<short>,
+                        state_cb_loop, user_data.get());
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb stream";
+
+  std::unique_ptr<cubeb_stream, decltype(&cubeb_stream_destroy)>
+    cleanup_input_stream_at_exit(input_stream, cubeb_stream_destroy);
+
+  /* setup an output stream */
+  r = cubeb_stream_init(ctx, &output_stream, "Cubeb loopback output only",
+                        NULL, NULL, device_id.c_str(), &output_params, latency_frames,
+                        is_float ? data_cb_playback<float> : data_cb_playback<short>,
+                        state_cb_loop, user_data.get());
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb stream";
+
+  std::unique_ptr<cubeb_stream, decltype(&cubeb_stream_destroy)>
+    cleanup_output_stream_at_exit(output_stream, cubeb_stream_destroy);
+
+  cubeb_stream_start(input_stream);
+  cubeb_stream_start(output_stream);
+  delay(150);
+  cubeb_stream_stop(output_stream);
+  cubeb_stream_stop(input_stream);
+
+  /* access after stop should not happen, but lock just in case and to appease sanitization tools */
+  std::lock_guard<std::mutex> lock(user_data->user_state_mutex);
+  std::vector<double> & output_frames = user_data->output_frames;
+  std::vector<double> & input_frames = user_data->input_frames;
+  ASSERT_LE(output_frames.size(), input_frames.size())
+    << "#Output frames should be less or equal to #input frames";
+
+  size_t phase = find_phase(user_data->output_frames, user_data->input_frames, NUM_FRAMES_TO_OUTPUT);
+
+  /* extract vectors of just the relevant signal from output and input */
+  auto output_frames_signal_start = output_frames.begin();
+  auto output_frames_signal_end = output_frames.begin() + NUM_FRAMES_TO_OUTPUT;
+  std::vector<double> trimmed_output_frames(output_frames_signal_start, output_frames_signal_end);
+  auto input_frames_signal_start = input_frames.begin() + phase;
+  auto input_frames_signal_end = input_frames.begin() + phase + NUM_FRAMES_TO_OUTPUT;
+  std::vector<double> trimmed_input_frames(input_frames_signal_start, input_frames_signal_end);
+
+  compare_signals(trimmed_output_frames, trimmed_input_frames);
+}
+
+TEST(cubeb, loopback_device_selection)
+{
+  run_loopback_device_selection_test(true);
+  run_loopback_device_selection_test(false);
+}
diff --git a/media/libcubeb/gtest/test_mixer.cpp b/media/libcubeb/gtest/test_mixer.cpp
index fc9efefc551c..b7daea9a9a4a 100644
--- a/media/libcubeb/gtest/test_mixer.cpp
+++ b/media/libcubeb/gtest/test_mixer.cpp
@@ -114,7 +114,8 @@ downmix_test(float const * data, cubeb_channel_layout in_layout, cubeb_channel_l
     STREAM_FORMAT,
     STREAM_FREQUENCY,
     layout_infos[in_layout].channels,
-    in_layout
+    in_layout,
+    CUBEB_STREAM_PREF_NONE
   };
 
   cubeb_stream_params out_params = {
@@ -124,7 +125,8 @@ downmix_test(float const * data, cubeb_channel_layout in_layout, cubeb_channel_l
     // smaller than or equal to the input channels.
     (out_layout == CUBEB_LAYOUT_UNDEFINED) ?
       layout_infos[in_layout].channels : layout_infos[out_layout].channels,
-    out_layout
+    out_layout,
+    CUBEB_STREAM_PREF_NONE
    };
 
   if (!cubeb_should_downmix(&in_params, &out_params)) {
diff --git a/media/libcubeb/gtest/test_overload_callback.cpp b/media/libcubeb/gtest/test_overload_callback.cpp
index 73982ef67819..05c01e848838 100644
--- a/media/libcubeb/gtest/test_overload_callback.cpp
+++ b/media/libcubeb/gtest/test_overload_callback.cpp
@@ -68,6 +68,7 @@ TEST(cubeb, overload_callback)
   output_params.rate = 48000;
   output_params.channels = 2;
   output_params.layout = CUBEB_LAYOUT_STEREO;
+  output_params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_get_min_latency(ctx, &output_params, &latency_frames);
   ASSERT_EQ(r, CUBEB_OK);
diff --git a/media/libcubeb/gtest/test_record.cpp b/media/libcubeb/gtest/test_record.cpp
index b25eb8abd18c..635beeebdc48 100644
--- a/media/libcubeb/gtest/test_record.cpp
+++ b/media/libcubeb/gtest/test_record.cpp
@@ -94,6 +94,7 @@ TEST(cubeb, record)
   params.rate = SAMPLE_FREQUENCY;
   params.channels = 1;
   params.layout = CUBEB_LAYOUT_UNDEFINED;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "Cubeb record (mono)", NULL, &params, NULL, nullptr,
                         4096, data_cb_record, state_cb_record, &stream_state);
diff --git a/media/libcubeb/gtest/test_resampler.cpp b/media/libcubeb/gtest/test_resampler.cpp
index 1f5fb8f9e14c..a5c335f94a91 100644
--- a/media/libcubeb/gtest/test_resampler.cpp
+++ b/media/libcubeb/gtest/test_resampler.cpp
@@ -333,6 +333,7 @@ void test_resampler_duplex(uint32_t input_channels, uint32_t output_channels,
   input_params.rate = input_rate;
   state.output_rate = output_params.rate = output_rate;
   state.target_rate = target_rate;
+  input_params.prefs = output_params.prefs = CUBEB_STREAM_PREF_NONE;
   long got;
 
   cubeb_resampler * resampler =
diff --git a/media/libcubeb/gtest/test_sanity.cpp b/media/libcubeb/gtest/test_sanity.cpp
index db441d416488..d3546d6f0cbb 100644
--- a/media/libcubeb/gtest/test_sanity.cpp
+++ b/media/libcubeb/gtest/test_sanity.cpp
@@ -125,6 +125,8 @@ TEST(cubeb, context_variables)
   params.format = STREAM_FORMAT;
   params.rate = STREAM_RATE;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
+
   r = cubeb_get_min_latency(ctx, &params, &value);
   ASSERT_TRUE(r == CUBEB_OK || r == CUBEB_ERROR_NOT_SUPPORTED);
   if (r == CUBEB_OK) {
@@ -160,6 +162,7 @@ TEST(cubeb, init_destroy_stream)
   params.rate = STREAM_RATE;
   params.channels = STREAM_CHANNELS;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
                         test_data_callback, test_state_callback, &dummy);
@@ -186,6 +189,7 @@ TEST(cubeb, init_destroy_multiple_streams)
   params.rate = STREAM_RATE;
   params.channels = STREAM_CHANNELS;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   for (i = 0; i < ARRAY_LENGTH(stream); ++i) {
     r = cubeb_stream_init(ctx, &stream[i], "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
@@ -216,6 +220,7 @@ TEST(cubeb, configure_stream)
   params.rate = STREAM_RATE;
   params.channels = 2; // panning
   params.layout = CUBEB_LAYOUT_STEREO;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
                         test_data_callback, test_state_callback, &dummy);
@@ -247,6 +252,7 @@ TEST(cubeb, configure_stream_undefined_layout)
   params.rate = STREAM_RATE;
   params.channels = 2; // panning
   params.layout = CUBEB_LAYOUT_UNDEFINED;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
                         test_data_callback, test_state_callback, &dummy);
@@ -282,6 +288,7 @@ test_init_start_stop_destroy_multiple_streams(int early, int delay_ms)
   params.rate = STREAM_RATE;
   params.channels = STREAM_CHANNELS;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   for (i = 0; i < ARRAY_LENGTH(stream); ++i) {
     r = cubeb_stream_init(ctx, &stream[i], "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
@@ -366,6 +373,7 @@ TEST(cubeb, init_destroy_multiple_contexts_and_streams)
   params.rate = STREAM_RATE;
   params.channels = STREAM_CHANNELS;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   for (i = 0; i < ARRAY_LENGTH(ctx); ++i) {
     r = common_init(&ctx[i], "test_sanity");
@@ -404,6 +412,7 @@ TEST(cubeb, basic_stream_operations)
   params.rate = STREAM_RATE;
   params.channels = STREAM_CHANNELS;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
                         test_data_callback, test_state_callback, &dummy);
@@ -452,6 +461,7 @@ TEST(cubeb, stream_position)
   params.rate = STREAM_RATE;
   params.channels = STREAM_CHANNELS;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
                         test_data_callback, test_state_callback, &dummy);
@@ -585,6 +595,7 @@ TEST(cubeb, drain)
   params.rate = STREAM_RATE;
   params.channels = STREAM_CHANNELS;
   params.layout = STREAM_LAYOUT;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   r = cubeb_stream_init(ctx, &stream, "test", NULL, NULL, NULL, &params, STREAM_LATENCY,
                         test_drain_data_callback, test_drain_state_callback, &dummy);
diff --git a/media/libcubeb/gtest/test_tone.cpp b/media/libcubeb/gtest/test_tone.cpp
index 3cfc0b012865..09bc2a754d25 100644
--- a/media/libcubeb/gtest/test_tone.cpp
+++ b/media/libcubeb/gtest/test_tone.cpp
@@ -95,6 +95,7 @@ TEST(cubeb, tone)
   params.rate = SAMPLE_FREQUENCY;
   params.channels = 1;
   params.layout = CUBEB_LAYOUT_MONO;
+  params.prefs = CUBEB_STREAM_PREF_NONE;
 
   std::unique_ptr<cb_user_data> user_data(new cb_user_data());
   ASSERT_TRUE(!!user_data) << "Error allocating user data";
diff --git a/media/libcubeb/include/cubeb.h b/media/libcubeb/include/cubeb.h
index 6d3f195cfb4e..64f3a8d0f2e2 100644
--- a/media/libcubeb/include/cubeb.h
+++ b/media/libcubeb/include/cubeb.h
@@ -53,16 +53,18 @@ extern "C" {
     output_params.format = CUBEB_SAMPLE_FLOAT32NE;
     output_params.rate = rate;
     output_params.channels = 2;
+    output_params.prefs = CUBEB_STREAM_PREF_NONE;
 
     cubeb_stream_params input_params;
     input_params.format = CUBEB_SAMPLE_FLOAT32NE;
     input_params.rate = rate;
     input_params.channels = 1;
+    input_params.prefs = CUBEB_STREAM_PREF_NONE;
 
     cubeb_stream * stm;
     rv = cubeb_stream_init(app_ctx, &stm, "Example Stream 1",
-                           NULL, input_params,
-                           NULL, output_params,
+                           NULL, &input_params,
+                           NULL, &output_params,
                            latency_frames,
                            data_cb, state_cb,
                            NULL);
@@ -213,6 +215,15 @@ typedef enum {
   CUBEB_LAYOUT_MAX
 } cubeb_channel_layout;
 
+/** Miscellaneous stream preferences. */
+typedef enum {
+  CUBEB_STREAM_PREF_NONE     = 0x00, /**< No stream preferences are requested. */
+  CUBEB_STREAM_PREF_LOOPBACK = 0x01 /**< Request a loopback stream. Should be
+                                         specified on the input params and an
+                                         output device to loopback from should
+                                         be passed in place of an input device. */
+} cubeb_stream_prefs;
+
 /** Stream format initialization parameters. */
 typedef struct {
   cubeb_sample_format format;   /**< Requested sample format.  One of
@@ -220,6 +231,7 @@ typedef struct {
   uint32_t rate;                /**< Requested sample rate.  Valid range is [1000, 192000]. */
   uint32_t channels;            /**< Requested channel count.  Valid range is [1, 8]. */
   cubeb_channel_layout layout;  /**< Requested channel layout. This must be consistent with the provided channels. */
+  cubeb_stream_prefs prefs;     /**< Requested preferences. */
 } cubeb_stream_params;
 
 /** Audio device description */
diff --git a/media/libcubeb/src/cubeb_alsa.c b/media/libcubeb/src/cubeb_alsa.c
index 8cb37ee96c77..f77d2522a862 100644
--- a/media/libcubeb/src/cubeb_alsa.c
+++ b/media/libcubeb/src/cubeb_alsa.c
@@ -890,6 +890,10 @@ alsa_stream_init_single(cubeb * ctx, cubeb_stream ** stream, char const * stream
 
   *stream = NULL;
 
+  if (stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK) {
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
+
   switch (stream_params->format) {
   case CUBEB_SAMPLE_S16LE:
     format = SND_PCM_FORMAT_S16_LE;
diff --git a/media/libcubeb/src/cubeb_audiounit.cpp b/media/libcubeb/src/cubeb_audiounit.cpp
index c1e95ef7d7aa..0e137eda8b50 100644
--- a/media/libcubeb/src/cubeb_audiounit.cpp
+++ b/media/libcubeb/src/cubeb_audiounit.cpp
@@ -135,8 +135,8 @@ struct cubeb_stream {
   cubeb_device_changed_callback device_changed_callback = nullptr;
   owned_critical_section device_changed_callback_lock;
   /* Stream creation parameters */
-  cubeb_stream_params input_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED };
-  cubeb_stream_params output_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED };
+  cubeb_stream_params input_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED, CUBEB_STREAM_PREF_NONE };
+  cubeb_stream_params output_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED, CUBEB_STREAM_PREF_NONE };
   device_info input_device;
   device_info output_device;
   /* User pointer of data_callback */
@@ -2360,6 +2360,12 @@ audiounit_setup_stream(cubeb_stream * stm)
 {
   stm->mutex.assert_current_thread_owns();
 
+  if ((stm->input_stream_params.prefs & CUBEB_STREAM_PREF_LOOPBACK) ||
+      (stm->output_stream_params.prefs & CUBEB_STREAM_PREF_LOOPBACK)) {
+    LOG("(%p) Loopback not supported for audiounit.", stm);
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
+
   int r = 0;
 
   device_info in_dev_info = stm->input_device;
diff --git a/media/libcubeb/src/cubeb_jack.cpp b/media/libcubeb/src/cubeb_jack.cpp
index 3b9574a3e8c1..f1a2d7847470 100644
--- a/media/libcubeb/src/cubeb_jack.cpp
+++ b/media/libcubeb/src/cubeb_jack.cpp
@@ -743,6 +743,12 @@ cbjack_stream_init(cubeb * context, cubeb_stream ** stream, char const * stream_
   if (input_device || output_device)
     return CUBEB_ERROR_NOT_SUPPORTED;
 
+  // Loopback is unsupported
+  if ((input_stream_params && (input_stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK)) ||
+      (output_stream_params && (output_stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK))) {
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
+
   *stream = NULL;
 
   // Find a free stream.
diff --git a/media/libcubeb/src/cubeb_opensl.c b/media/libcubeb/src/cubeb_opensl.c
index 903906d046ed..4eaedbb888c4 100644
--- a/media/libcubeb/src/cubeb_opensl.c
+++ b/media/libcubeb/src/cubeb_opensl.c
@@ -1291,6 +1291,11 @@ opensl_validate_stream_param(cubeb_stream_params * stream_params)
        (stream_params->channels < 1 || stream_params->channels > 32))) {
     return CUBEB_ERROR_INVALID_FORMAT;
   }
+  if ((stream_params &&
+       (stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK))) {
+    LOG("Loopback is not supported");
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
   return CUBEB_OK;
 }
 
diff --git a/media/libcubeb/src/cubeb_pulse.c b/media/libcubeb/src/cubeb_pulse.c
index 19c2a84c590e..31ec534c5136 100644
--- a/media/libcubeb/src/cubeb_pulse.c
+++ b/media/libcubeb/src/cubeb_pulse.c
@@ -807,6 +807,9 @@ create_pa_stream(cubeb_stream * stm,
          (stream_params->layout == CUBEB_LAYOUT_UNDEFINED ||
          (stream_params->layout != CUBEB_LAYOUT_UNDEFINED &&
          CUBEB_CHANNEL_LAYOUT_MAPS[stream_params->layout].channels == stream_params->channels))));
+  if (stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK) {
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
   *pa_stm = NULL;
   pa_sample_spec ss;
   ss.format = to_pulse_format(stream_params->format);
diff --git a/media/libcubeb/src/cubeb_sndio.c b/media/libcubeb/src/cubeb_sndio.c
index c470a294c1fe..1699677e54fa 100644
--- a/media/libcubeb/src/cubeb_sndio.c
+++ b/media/libcubeb/src/cubeb_sndio.c
@@ -279,11 +279,19 @@ sndio_stream_init(cubeb * context,
   memset(s, 0, sizeof(cubeb_stream));
   s->mode = 0;
   if (input_stream_params) {
+    if (input_stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK) {
+      DPR("sndio_stream_init(), loopback not supported\n");
+      goto err;
+    }
     s->mode |= SIO_REC;
     format = input_stream_params->format;
     rate = input_stream_params->rate;
   }
   if (output_stream_params) {
+    if (output_stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK) {
+      DPR("sndio_stream_init(), loopback not supported\n");
+      goto err;
+    }
     s->mode |= SIO_PLAY;
     format = output_stream_params->format;
     rate = output_stream_params->rate;
diff --git a/media/libcubeb/src/cubeb_wasapi.cpp b/media/libcubeb/src/cubeb_wasapi.cpp
index 0efc6b192800..0de14348ae4f 100644
--- a/media/libcubeb/src/cubeb_wasapi.cpp
+++ b/media/libcubeb/src/cubeb_wasapi.cpp
@@ -193,12 +193,12 @@ struct cubeb_stream {
   /* Mixer pameters. We need to convert the input stream to this
      samplerate/channel layout, as WASAPI does not resample nor upmix
      itself. */
-  cubeb_stream_params input_mix_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED };
-  cubeb_stream_params output_mix_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED };
+  cubeb_stream_params input_mix_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED, CUBEB_STREAM_PREF_NONE };
+  cubeb_stream_params output_mix_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED, CUBEB_STREAM_PREF_NONE };
   /* Stream parameters. This is what the client requested,
    * and what will be presented in the callback. */
-  cubeb_stream_params input_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED };
-  cubeb_stream_params output_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED };
+  cubeb_stream_params input_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED, CUBEB_STREAM_PREF_NONE };
+  cubeb_stream_params output_stream_params = { CUBEB_SAMPLE_FLOAT32NE, 0, 0, CUBEB_LAYOUT_UNDEFINED, CUBEB_STREAM_PREF_NONE };
   /* The input and output device, or NULL for default. */
   std::unique_ptr<const wchar_t[]> input_device;
   std::unique_ptr<const wchar_t[]> output_device;
@@ -207,6 +207,10 @@ struct cubeb_stream {
   cubeb_state_callback state_callback = nullptr;
   cubeb_data_callback data_callback = nullptr;
   wasapi_refill_callback refill_callback = nullptr;
+  /* True when a loopback device is requested with no output device. In this
+     case a dummy output device is opened to drive the loopback, but should not
+     be exposed. */
+  bool has_dummy_output = false;
   void * user_ptr = nullptr;
   /* Lifetime considerations:
      - client, render_client, audio_clock and audio_stream_volume are interface
@@ -564,9 +568,9 @@ refill(cubeb_stream * stm, void * input_buffer, long input_frames_count,
 {
   XASSERT(!stm->draining);
   /* If we need to upmix after resampling, resample into the mix buffer to
-     avoid a copy. */
+     avoid a copy. Avoid exposing output if it is a dummy stream. */
   void * dest = nullptr;
-  if (has_output(stm)) {
+  if (has_output(stm) && !stm->has_dummy_output) {
     if (cubeb_should_mix(&stm->output_stream_params, &stm->output_mix_params)) {
       dest = stm->mix_buffer.data();
     } else {
@@ -595,9 +599,10 @@ refill(cubeb_stream * stm, void * input_buffer, long input_frames_count,
 
   /* If this is not true, there will be glitches.
      It is alright to have produced less frames if we are draining, though. */
-  XASSERT(out_frames == output_frames_needed || stm->draining || !has_output(stm));
+  XASSERT(out_frames == output_frames_needed || stm->draining || !has_output(stm) || stm->has_dummy_output);
 
-  if (has_output(stm) && cubeb_should_mix(&stm->output_stream_params, &stm->output_mix_params)) {
+  // We don't bother mixing dummy output as it will be silenced, otherwise mix output if needed
+  if (!stm->has_dummy_output && has_output(stm) && cubeb_should_mix(&stm->output_stream_params, &stm->output_mix_params)) {
     XASSERT(dest == stm->mix_buffer.data());
     unsigned long dest_len = out_frames * stm->output_stream_params.channels;
     XASSERT(dest_len <= stm->mix_buffer.size() / stm->bytes_per_sample);
@@ -612,22 +617,12 @@ refill(cubeb_stream * stm, void * input_buffer, long input_frames_count,
 
 /* This helper grabs all the frames available from a capture client, put them in
  * linear_input_buffer. linear_input_buffer should be cleared before the
- * callback exits. */
+ * callback exits. This helper does not work with exclusive mode streams. */
 bool get_input_buffer(cubeb_stream * stm)
 {
-  HRESULT hr;
-  UINT32 padding_in;
-
   XASSERT(has_input(stm));
 
-  hr = stm->input_client->GetCurrentPadding(&padding_in);
-  if (FAILED(hr)) {
-    LOG("Failed to get padding");
-    return false;
-  }
-  XASSERT(padding_in <= stm->input_buffer_frame_count);
-  UINT32 total_available_input = padding_in;
-
+  HRESULT hr;
   BYTE * input_packet = NULL;
   DWORD flags;
   UINT64 dev_pos;
@@ -635,17 +630,18 @@ bool get_input_buffer(cubeb_stream * stm)
   /* Get input packets until we have captured enough frames, and put them in a
    * contiguous buffer. */
   uint32_t offset = 0;
-  while (offset != total_available_input) {
-    hr = stm->capture_client->GetNextPacketSize(&next);
+  // If the input stream is event driven we should only ever expect to read a
+  // single packet each time. However, if we're pulling from the stream we may
+  // need to grab multiple packets worth of frames that have accumulated (so
+  // need a loop).
+  for (hr = stm->capture_client->GetNextPacketSize(&next);
+       next > 0;
+       hr = stm->capture_client->GetNextPacketSize(&next)) {
+
     if (FAILED(hr)) {
       LOG("cannot get next packet size: %lx", hr);
       return false;
     }
-    /* This can happen if the capture stream has stopped. Just return in this
-     * case. */
-    if (!next) {
-      break;
-    }
 
     UINT32 packet_size;
     hr = stm->capture_client->GetBuffer(&input_packet,
@@ -658,6 +654,21 @@ bool get_input_buffer(cubeb_stream * stm)
       return false;
     }
     XASSERT(packet_size == next);
+    // We do not explicitly handle the AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY
+    // flag. There a two primary (non exhaustive) scenarios we anticipate this
+    // flag being set in:
+    //   - The first GetBuffer after Start has this flag undefined. In this
+    //     case the flag may be set but is meaningless and can be ignored.
+    //   - If a glitch is introduced into the input. This should not happen
+    //     for event based inputs, and should be mitigated by using a dummy
+    //     stream to drive input in the case of input only loopback. Without
+    //     a dummy output, input only loopback would glitch on silence. However,
+    //     the dummy input should push silence to the loopback and prevent
+    //     discontinuities. See https://blogs.msdn.microsoft.com/matthew_van_eerde/2008/12/16/sample-wasapi-loopback-capture-record-what-you-hear/
+    // As the first scenario can be ignored, and we anticipate the second
+    // scenario is mitigated, we ignore the flag.
+    // For more info: https://msdn.microsoft.com/en-us/library/windows/desktop/dd370859(v=vs.85).aspx,
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/dd371458(v=vs.85).aspx
     if (flags & AUDCLNT_BUFFERFLAGS_SILENT) {
       LOG("insert silence: ps=%u", packet_size);
       stm->linear_input_buffer->push_silence(packet_size * stm->input_stream_params.channels);
@@ -687,8 +698,7 @@ bool get_input_buffer(cubeb_stream * stm)
     offset += packet_size;
   }
 
-  XASSERT(stm->linear_input_buffer->length() >= total_available_input &&
-          offset == total_available_input);
+  XASSERT(stm->linear_input_buffer->length() >= offset);
 
   return true;
 }
@@ -774,18 +784,36 @@ refill_callback_duplex(cubeb_stream * stm)
     return false;
   }
 
-  ALOGV("Duplex callback: input frames: %Iu, output frames: %Iu",
-        input_frames, output_frames);
+  if (stm->has_dummy_output) {
+    ALOGV("Duplex callback (dummy output): input frames: %Iu, output frames: %Iu",
+          input_frames, output_frames);
 
-  refill(stm,
-         stm->linear_input_buffer->data(),
-         input_frames,
-         output_buffer,
-         output_frames);
+    // We don't want to expose the dummy output to the callback so don't pass
+    // the output buffer (it will be released later with silence in it)
+    refill(stm,
+           stm->linear_input_buffer->data(),
+           input_frames,
+           nullptr,
+           0);
+  } else {
+    ALOGV("Duplex callback: input frames: %Iu, output frames: %Iu",
+          input_frames, output_frames);
+
+    refill(stm,
+           stm->linear_input_buffer->data(),
+           input_frames,
+           output_buffer,
+           output_frames);
+  }
 
   stm->linear_input_buffer->clear();
 
-  hr = stm->render_client->ReleaseBuffer(output_frames, 0);
+  if (stm->has_dummy_output) {
+    // If output is a dummy output, make sure it's silent
+    hr = stm->render_client->ReleaseBuffer(output_frames, AUDCLNT_BUFFERFLAGS_SILENT);
+  } else {
+    hr = stm->render_client->ReleaseBuffer(output_frames, 0);
+  }
   if (FAILED(hr)) {
     LOG("failed to release buffer: %lx", hr);
     return false;
@@ -1517,6 +1545,11 @@ int setup_wasapi_stream_one_side(cubeb_stream * stm,
 {
   com_ptr<IMMDevice> device;
   HRESULT hr;
+  bool is_loopback = stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK;
+  if (is_loopback && direction != eCapture) {
+    LOG("Loopback pref can only be used with capture streams!\n");
+    return CUBEB_ERROR;
+  }
 
   stm->stream_reset_lock.assert_current_thread_owns();
   bool try_again = false;
@@ -1530,9 +1563,16 @@ int setup_wasapi_stream_one_side(cubeb_stream * stm,
         return CUBEB_ERROR;
       }
     } else {
-      hr = get_default_endpoint(device, direction);
+      // If caller has requested loopback but not specified a device, look for
+      // the default render device. Otherwise look for the default device
+      // appropriate to the direction.
+      hr = get_default_endpoint(device, is_loopback ? eRender : direction);
       if (FAILED(hr)) {
-        LOG("Could not get default %s endpoint, error: %lx\n", DIRECTION_NAME, hr);
+        if (is_loopback) {
+          LOG("Could not get default render endpoint for loopback, error: %lx\n", hr);
+        } else {
+          LOG("Could not get default %s endpoint, error: %lx\n", DIRECTION_NAME, hr);
+        }
         return CUBEB_ERROR;
       }
     }
@@ -1603,9 +1643,18 @@ int setup_wasapi_stream_one_side(cubeb_stream * stm,
       mix_params->format, mix_params->rate, mix_params->channels,
       CUBEB_CHANNEL_LAYOUT_MAPS[mix_params->layout].name);
 
+  DWORD flags = AUDCLNT_STREAMFLAGS_NOPERSIST;
+
+  // Check if a loopback device should be requested. Note that event callbacks
+  // do not work with loopback devices, so only request these if not looping.
+  if (is_loopback) {
+    flags |= AUDCLNT_STREAMFLAGS_LOOPBACK;
+  } else {
+    flags |= AUDCLNT_STREAMFLAGS_EVENTCALLBACK;
+  }
+
   hr = audio_client->Initialize(AUDCLNT_SHAREMODE_SHARED,
-                                AUDCLNT_STREAMFLAGS_EVENTCALLBACK |
-                                AUDCLNT_STREAMFLAGS_NOPERSIST,
+                                flags,
                                 frames_to_hns(stm, stm->latency),
                                 0,
                                 mix_format.get(),
@@ -1626,11 +1675,14 @@ int setup_wasapi_stream_one_side(cubeb_stream * stm,
     stm->mix_buffer.resize(frames_to_bytes_before_mix(stm, *buffer_frame_count));
   }
 
-  hr = audio_client->SetEventHandle(event);
-  if (FAILED(hr)) {
-    LOG("Could set the event handle for the %s client %lx.",
-        DIRECTION_NAME, hr);
-    return CUBEB_ERROR;
+  // Events are used if not looping back
+  if (!is_loopback) {
+    hr = audio_client->SetEventHandle(event);
+    if (FAILED(hr)) {
+      LOG("Could set the event handle for the %s client %lx.",
+          DIRECTION_NAME, hr);
+      return CUBEB_ERROR;
+    }
   }
 
   hr = audio_client->GetService(riid, render_or_capture_client.receive_vpp());
@@ -1691,6 +1743,27 @@ int setup_wasapi_stream(cubeb_stream * stm)
                                            silent_buffer_count);
   }
 
+  // If we don't have an output device but are requesting a loopback device,
+  // we attempt to open that same device in output mode in order to drive the
+  // loopback via the output events.
+  stm->has_dummy_output = false;
+  if (!has_output(stm) && stm->input_stream_params.prefs & CUBEB_STREAM_PREF_LOOPBACK) {
+    stm->output_stream_params.rate = stm->input_stream_params.rate;
+    stm->output_stream_params.channels = stm->input_stream_params.channels;
+    stm->output_stream_params.layout = stm->input_stream_params.layout;
+    if (stm->input_device) {
+      size_t len = wcslen(stm->input_device.get());
+      std::unique_ptr<wchar_t[]> tmp(new wchar_t[len + 1]);
+      if (wcsncpy_s(tmp.get(), len + 1, stm->input_device.get(), len) != 0) {
+        LOG("Failed to copy device identifier while copying input stream"
+            " configuration to output stream configuration to drive loopback.");
+        return CUBEB_ERROR;
+      }
+      stm->output_device = move(tmp);
+    }
+    stm->has_dummy_output = true;
+  }
+
   if (has_output(stm)) {
     LOG("(%p) Setup render: device=%p", stm, stm->output_device.get());
     rv = setup_wasapi_stream_one_side(stm,
diff --git a/media/libcubeb/src/cubeb_winmm.c b/media/libcubeb/src/cubeb_winmm.c
index b5aab51e8316..e62eed640ec6 100644
--- a/media/libcubeb/src/cubeb_winmm.c
+++ b/media/libcubeb/src/cubeb_winmm.c
@@ -414,6 +414,11 @@ winmm_stream_init(cubeb * context, cubeb_stream ** stream, char const * stream_n
     return CUBEB_ERROR_DEVICE_UNAVAILABLE;
   }
 
+  if (output_stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK) {
+    /* Loopback is not supported */
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
+
   *stream = NULL;
 
   memset(&wfx, 0, sizeof(wfx));
diff --git a/media/libcubeb/update.sh b/media/libcubeb/update.sh
index 555fda62c605..827a0db37c50 100755
--- a/media/libcubeb/update.sh
+++ b/media/libcubeb/update.sh
@@ -42,6 +42,7 @@ cp $1/test/test_audio.cpp gtest
 cp $1/test/test_devices.cpp gtest
 cp $1/test/test_duplex.cpp gtest
 cp $1/test/test_latency.cpp gtest
+cp $1/test/test_loopback.cpp gtest
 cp $1/test/test_mixer.cpp gtest
 cp $1/test/test_overload_callback.cpp gtest
 cp $1/test/test_record.cpp gtest
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index b52aaa09a737..93fec091a857 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5808,9 +5808,6 @@ pref("media.block-autoplay-until-in-foreground", true);
 // Is Stylo CSS support built and enabled?
 // Only define these prefs if Stylo support is actually built in.
 #ifdef MOZ_STYLO
-// XXX: We should flip this pref to true once the blocked_domains is non-empty.
-pref("layout.css.stylo-blocklist.enabled", false);
-pref("layout.css.stylo-blocklist.blocked_domains", "");
 #ifdef MOZ_STYLO_ENABLE
 pref("layout.css.servo.enabled", true);
 #else
diff --git a/servo/Cargo.lock b/servo/Cargo.lock
index 7da6667c3178..8e5907fe7f4d 100644
--- a/servo/Cargo.lock
+++ b/servo/Cargo.lock
@@ -1024,7 +1024,6 @@ dependencies = [
  "simd 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
- "style_traits 0.0.1",
  "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "truetype 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-bidi 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/servo/components/gfx/Cargo.toml b/servo/components/gfx/Cargo.toml
index 2fc3924cdce5..7d14ebd31e83 100644
--- a/servo/components/gfx/Cargo.toml
+++ b/servo/components/gfx/Cargo.toml
@@ -40,7 +40,6 @@ servo_geometry = {path = "../geometry"}
 servo_url = {path = "../url"}
 smallvec = "0.6"
 style = {path = "../style"}
-style_traits = {path = "../style_traits"}
 time = "0.1.12"
 unicode-bidi = {version = "0.3", features = ["with_serde"]}
 unicode-script = {version = "0.1", features = ["harfbuzz"]}
diff --git a/servo/components/gfx/display_list/mod.rs b/servo/components/gfx/display_list/mod.rs
index d481ef170173..a3abba8fd294 100644
--- a/servo/components/gfx/display_list/mod.rs
+++ b/servo/components/gfx/display_list/mod.rs
@@ -29,14 +29,13 @@ use std::collections::HashMap;
 use std::f32;
 use std::fmt;
 use std::sync::Arc;
-use style::values::computed::Filter;
-use style_traits::cursor::CursorKind;
 use text::TextRun;
 use text::glyph::ByteIndex;
-use webrender_api::{BoxShadowClipMode, ClipId, ColorF, ExtendMode, GradientStop, ImageKey};
-use webrender_api::{ImageRendering, LayoutPoint, LayoutRect, LayoutSize, LayoutVector2D};
-use webrender_api::{LineStyle, LocalClip, MixBlendMode, NormalBorder, RepeatMode, ScrollPolicy};
-use webrender_api::{ScrollSensitivity, StickyOffsetBounds, TransformStyle};
+use webrender_api::{BorderRadius, BorderWidths, BoxShadowClipMode, ClipId, ColorF, ExtendMode};
+use webrender_api::{FilterOp, GradientStop, ImageBorder, ImageKey, ImageRendering, LayoutPoint};
+use webrender_api::{LayoutRect, LayoutSize, LayoutVector2D, LineStyle, LocalClip, MixBlendMode};
+use webrender_api::{NormalBorder, ScrollPolicy, ScrollSensitivity, StickyOffsetBounds};
+use webrender_api::TransformStyle;
 
 pub use style::dom::OpaqueNode;
 
@@ -204,7 +203,7 @@ pub struct StackingContext {
     pub z_index: i32,
 
     /// CSS filters to be applied to this stacking context (including opacity).
-    pub filters: Vec<Filter>,
+    pub filters: Vec<FilterOp>,
 
     /// The blend mode with which this stacking context blends with its backdrop.
     pub mix_blend_mode: MixBlendMode,
@@ -233,7 +232,7 @@ impl StackingContext {
                bounds: &Rect<Au>,
                overflow: &Rect<Au>,
                z_index: i32,
-               filters: Vec<Filter>,
+               filters: Vec<FilterOp>,
                mix_blend_mode: MixBlendMode,
                transform: Option<Transform3D<f32>>,
                transform_style: TransformStyle,
@@ -370,7 +369,7 @@ pub struct ClipScrollNode {
     pub clip: ClippingRegion,
 
     /// The rect of the contents that can be scrolled inside of the scroll root.
-    pub content_rect: Rect<Au>,
+    pub content_rect: LayoutRect,
 
     /// The type of this ClipScrollNode.
     pub node_type: ClipScrollNodeType,
@@ -419,7 +418,7 @@ pub struct BaseDisplayItem {
 
 impl BaseDisplayItem {
     #[inline(always)]
-    pub fn new(bounds: &Rect<Au>,
+    pub fn new(bounds: Rect<Au>,
                metadata: DisplayItemMetadata,
                local_clip: LocalClip,
                section: DisplayListSection,
@@ -427,12 +426,12 @@ impl BaseDisplayItem {
                clipping_and_scrolling: ClippingAndScrolling)
                -> BaseDisplayItem {
         BaseDisplayItem {
-            bounds: *bounds,
-            metadata: metadata,
-            local_clip: local_clip,
-            section: section,
-            stacking_context_id: stacking_context_id,
-            clipping_and_scrolling: clipping_and_scrolling,
+            bounds,
+            metadata,
+            local_clip,
+            section,
+            stacking_context_id,
+            clipping_and_scrolling,
         }
     }
 
@@ -646,7 +645,7 @@ pub struct DisplayItemMetadata {
     pub node: OpaqueNode,
     /// The value of the `cursor` property when the mouse hovers over this display item. If `None`,
     /// this display item is ineligible for pointer events (`pointer-events: none`).
-    pub pointing: Option<CursorKind>,
+    pub pointing: Option<u16>,
 }
 
 /// Paints a solid color.
@@ -789,28 +788,6 @@ pub struct RadialGradientDisplayItem {
     pub tile_spacing: LayoutSize,
 }
 
-/// A border that is made of image segments.
-#[derive(Clone, Deserialize, MallocSizeOf, Serialize)]
-pub struct ImageBorder {
-    /// The image this border uses, border-image-source.
-    pub image: WebRenderImageInfo,
-
-    /// How to slice the image, as per border-image-slice.
-    pub slice: SideOffsets2D<u32>,
-
-    /// Outsets for the border, as per border-image-outset.
-    pub outset: SideOffsets2D<f32>,
-
-    /// If fill is true, draw the center patch of the image.
-    pub fill: bool,
-
-    /// How to repeat or stretch horizontal edges (border-image-repeat).
-    pub repeat_horizontal: RepeatMode,
-
-    /// How to repeat or stretch vertical edges (border-image-repeat).
-    pub repeat_vertical: RepeatMode,
-}
-
 /// A border that is made of linear gradient
 #[derive(Clone, Deserialize, MallocSizeOf, Serialize)]
 pub struct GradientBorder {
@@ -847,7 +824,7 @@ pub struct BorderDisplayItem {
     pub base: BaseDisplayItem,
 
     /// Border widths.
-    pub border_widths: SideOffsets2D<Au>,
+    pub border_widths: BorderWidths,
 
     /// Details for specific border type
     pub details: BorderDetails,
@@ -949,7 +926,7 @@ pub struct BoxShadowDisplayItem {
     pub spread_radius: f32,
 
     /// The border radius of this shadow.
-    pub border_radius: BorderRadii<Au>,
+    pub border_radius: BorderRadius,
 
     /// How we should clip the result.
     pub clip_mode: BoxShadowClipMode,
diff --git a/servo/components/gfx/lib.rs b/servo/components/gfx/lib.rs
index 418e8d7f8970..361844bce6b8 100644
--- a/servo/components/gfx/lib.rs
+++ b/servo/components/gfx/lib.rs
@@ -58,7 +58,6 @@ extern crate servo_url;
 extern crate simd;
 extern crate smallvec;
 extern crate style;
-extern crate style_traits;
 extern crate time;
 extern crate unicode_bidi;
 extern crate unicode_script;
diff --git a/servo/components/layout/display_list/builder.rs b/servo/components/layout/display_list/builder.rs
index d66fe380734e..bb60018b389b 100644
--- a/servo/components/layout/display_list/builder.rs
+++ b/servo/components/layout/display_list/builder.rs
@@ -30,7 +30,7 @@ use gfx::display_list::{BaseDisplayItem, BorderDetails, BorderDisplayItem, BLUR_
 use gfx::display_list::{BorderRadii, BoxShadowDisplayItem, ClipScrollNode};
 use gfx::display_list::{ClipScrollNodeIndex, ClipScrollNodeType, ClippingAndScrolling};
 use gfx::display_list::{ClippingRegion, DisplayItem, DisplayItemMetadata, DisplayList};
-use gfx::display_list::{DisplayListSection, GradientDisplayItem, IframeDisplayItem, ImageBorder};
+use gfx::display_list::{DisplayListSection, GradientDisplayItem, IframeDisplayItem};
 use gfx::display_list::{ImageDisplayItem, LineDisplayItem, OpaqueNode};
 use gfx::display_list::{PopAllTextShadowsDisplayItem, PushTextShadowDisplayItem};
 use gfx::display_list::{RadialGradientDisplayItem, SolidColorDisplayItem, StackingContext};
@@ -68,15 +68,15 @@ use style::values::computed::{Gradient, NumberOrPercentage};
 use style::values::computed::effects::SimpleShadow;
 use style::values::computed::pointing::Cursor;
 use style::values::generics::background::BackgroundSize;
-use style::values::generics::effects::Filter;
 use style::values::generics::image::{GradientKind, Image, PaintWorklet};
 use style_traits::CSSPixel;
 use style_traits::ToCss;
 use style_traits::cursor::CursorKind;
 use table_cell::CollapsedBordersForCell;
-use webrender_api::{self, BoxShadowClipMode, ClipId, ClipMode, ColorF, ComplexClipRegion};
-use webrender_api::{ImageRendering, LayoutSize, LayoutVector2D, LineStyle};
-use webrender_api::{LocalClip, NormalBorder, ScrollPolicy, ScrollSensitivity, StickyOffsetBounds};
+use webrender_api::{self, BorderSide, BoxShadowClipMode, ClipId, ClipMode, ColorF};
+use webrender_api::{ComplexClipRegion, FilterOp, ImageBorder, ImageRendering, LayoutRect};
+use webrender_api::{LayoutSize, LayoutVector2D, LineStyle, LocalClip, NinePatchDescriptor};
+use webrender_api::{NormalBorder, ScrollPolicy, ScrollSensitivity, StickyOffsetBounds};
 
 trait ResolvePercentage {
     fn resolve(&self, length: u32) -> u32;
@@ -246,7 +246,7 @@ impl StackingContextCollectionState {
             id: Some(ClipId::root_scroll_node(pipeline_id.to_webrender())),
             parent_index: ClipScrollNodeIndex(0),
             clip: ClippingRegion::from_rect(&TypedRect::zero()),
-            content_rect: Rect::zero(),
+            content_rect: LayoutRect::zero(),
             node_type: ClipScrollNodeType::ScrollFrame(ScrollSensitivity::ScriptAndInputEvents),
         };
 
@@ -387,10 +387,11 @@ impl<'a> DisplayListBuildState<'a> {
         };
 
         BaseDisplayItem::new(
-            &bounds,
+            *bounds,
             DisplayItemMetadata {
-                node: node,
-                pointing: cursor,
+                node,
+                // Store cursor id in display list.
+                pointing: cursor.map(|x| x as u16),
             },
             clip,
             section,
@@ -816,7 +817,7 @@ fn calculate_inner_bounds(mut bounds: Rect<Au>, offsets: SideOffsets2D<Au>) -> R
 }
 
 fn simple_normal_border(color: ColorF, style: webrender_api::BorderStyle) -> NormalBorder {
-    let side = webrender_api::BorderSide { color, style };
+    let side = BorderSide { color, style };
     NormalBorder {
         left: side,
         right: side,
@@ -844,6 +845,36 @@ fn calculate_inner_border_radii(
     radii
 }
 
+fn build_image_border_details(
+    webrender_image: WebRenderImageInfo,
+    border_style_struct: &style_structs::Border,
+) -> Option<BorderDetails> {
+    let corners = &border_style_struct.border_image_slice.offsets;
+    let border_image_repeat = &border_style_struct.border_image_repeat;
+    if let Some(image_key) = webrender_image.key {
+        Some(BorderDetails::Image(ImageBorder {
+            image_key: image_key,
+            patch: NinePatchDescriptor {
+                width: webrender_image.width,
+                height: webrender_image.height,
+                slice: SideOffsets2D::new(
+                    corners.0.resolve(webrender_image.height),
+                    corners.1.resolve(webrender_image.width),
+                    corners.2.resolve(webrender_image.height),
+                    corners.3.resolve(webrender_image.width),
+                ),
+            },
+            fill: border_style_struct.border_image_slice.fill,
+            // TODO(gw): Support border-image-outset
+            outset: SideOffsets2D::zero(),
+            repeat_horizontal: border_image_repeat.0.to_layout(),
+            repeat_vertical: border_image_repeat.1.to_layout(),
+        }))
+    } else {
+        None
+    }
+}
+
 impl FragmentDisplayListBuilding for Fragment {
     fn collect_stacking_contexts_for_blocklike_fragment(
         &mut self,
@@ -1292,7 +1323,7 @@ impl FragmentDisplayListBuilding for Fragment {
                 ),
                 blur_radius: box_shadow.base.blur.px(),
                 spread_radius: box_shadow.spread.px(),
-                border_radius,
+                border_radius: border_radius.to_border_radius(),
                 clip_mode: if box_shadow.inset {
                     BoxShadowClipMode::Inset
                 } else {
@@ -1352,13 +1383,6 @@ impl FragmentDisplayListBuilding for Fragment {
             );
         }
 
-        let colors = SideOffsets2D::new(
-            style.resolve_color(colors.top),
-            style.resolve_color(colors.right),
-            style.resolve_color(colors.bottom),
-            style.resolve_color(colors.left),
-        );
-
         // If this border collapses, then we draw outside the boundaries we were given.
         let mut bounds = *bounds;
         if let BorderPaintingMode::Collapse(collapsed_borders) = border_painting_mode {
@@ -1376,35 +1400,28 @@ impl FragmentDisplayListBuilding for Fragment {
 
         let border_radius = build_border_radius(&bounds, border_style_struct);
 
-        match border_style_struct.border_image_source {
-            Either::First(_) => {
-                state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
-                    base: base,
-                    border_widths: border.to_physical(style.writing_mode),
-                    details: BorderDetails::Normal(NormalBorder {
-                        left: webrender_api::BorderSide {
-                            color: colors.left.to_layout(),
-                            style: border_style.left.to_layout(),
-                        },
-                        right: webrender_api::BorderSide {
-                            color: colors.right.to_layout(),
-                            style: border_style.right.to_layout(),
-                        },
-                        top: webrender_api::BorderSide {
-                            color: colors.top.to_layout(),
-                            style: border_style.top.to_layout(),
-                        },
-                        bottom: webrender_api::BorderSide {
-                            color: colors.bottom.to_layout(),
-                            style: border_style.bottom.to_layout(),
-                        },
-                        radius: border_radius.to_border_radius(),
-                    }),
-                })));
-            },
+        let details = match border_style_struct.border_image_source {
+            Either::First(_) => Some(BorderDetails::Normal(NormalBorder {
+                left: BorderSide {
+                    color: style.resolve_color(colors.left).to_layout(),
+                    style: border_style.left.to_layout(),
+                },
+                right: BorderSide {
+                    color: style.resolve_color(colors.right).to_layout(),
+                    style: border_style.right.to_layout(),
+                },
+                top: BorderSide {
+                    color: style.resolve_color(colors.top).to_layout(),
+                    style: border_style.top.to_layout(),
+                },
+                bottom: BorderSide {
+                    color: style.resolve_color(colors.bottom).to_layout(),
+                    style: border_style.bottom.to_layout(),
+                },
+                radius: border_radius.to_border_radius(),
+            })),
             Either::Second(Image::Gradient(ref gradient)) => {
-                let border_widths = border.to_physical(style.writing_mode);
-                let details = match gradient.kind {
+                Some(match gradient.kind {
                     GradientKind::Linear(angle_or_corner) => {
                         BorderDetails::Gradient(display_list::GradientBorder {
                             gradient: convert_linear_gradient(
@@ -1430,80 +1447,39 @@ impl FragmentDisplayListBuilding for Fragment {
                             outset: SideOffsets2D::zero(),
                         })
                     },
-                };
-                state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
-                    base,
-                    border_widths,
-                    details,
-                })));
+                })
             },
             Either::Second(Image::PaintWorklet(ref paint_worklet)) => {
                 // TODO: this size should be increased by border-image-outset
                 let size = self.border_box.size.to_physical(style.writing_mode);
-                let webrender_image =
-                    self.get_webrender_image_for_paint_worklet(state, style, paint_worklet, size);
-                if let Some(webrender_image) = webrender_image {
-                    let corners = &border_style_struct.border_image_slice.offsets;
-                    let border_image_repeat = &border_style_struct.border_image_repeat;
-
-                    state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
-                        base: base,
-                        border_widths: border.to_physical(style.writing_mode),
-                        details: BorderDetails::Image(ImageBorder {
-                            image: webrender_image,
-                            fill: border_style_struct.border_image_slice.fill,
-                            slice: SideOffsets2D::new(
-                                corners.0.resolve(webrender_image.height),
-                                corners.1.resolve(webrender_image.width),
-                                corners.2.resolve(webrender_image.height),
-                                corners.3.resolve(webrender_image.width),
-                            ),
-                            // TODO(gw): Support border-image-outset
-                            outset: SideOffsets2D::zero(),
-                            repeat_horizontal: border_image_repeat.0.to_layout(),
-                            repeat_vertical: border_image_repeat.1.to_layout(),
-                        }),
-                    })));
-                }
+                self.get_webrender_image_for_paint_worklet(state, style, paint_worklet, size)
+                    .and_then(|image| build_image_border_details(image, border_style_struct))
             },
             Either::Second(Image::Rect(..)) => {
                 // TODO: Handle border-image with `-moz-image-rect`.
+                None
             },
             Either::Second(Image::Element(..)) => {
                 // TODO: Handle border-image with `-moz-element`.
+                None
             },
-            Either::Second(Image::Url(ref image_url)) => {
-                if let Some(url) = image_url.url() {
-                    let webrender_image = state.layout_context.get_webrender_image_for_url(
+            Either::Second(Image::Url(ref image_url)) => image_url
+                .url()
+                .and_then(|url| {
+                    state.layout_context.get_webrender_image_for_url(
                         self.node,
                         url.clone(),
                         UsePlaceholder::No,
-                    );
-                    if let Some(webrender_image) = webrender_image {
-                        let corners = &border_style_struct.border_image_slice.offsets;
-                        let border_image_repeat = &border_style_struct.border_image_repeat;
-
-                        state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
-                            base: base,
-                            border_widths: border.to_physical(style.writing_mode),
-                            details: BorderDetails::Image(ImageBorder {
-                                image: webrender_image,
-                                fill: border_style_struct.border_image_slice.fill,
-                                slice: SideOffsets2D::new(
-                                    corners.0.resolve(webrender_image.height),
-                                    corners.1.resolve(webrender_image.width),
-                                    corners.2.resolve(webrender_image.height),
-                                    corners.3.resolve(webrender_image.width),
-                                ),
-                                // TODO(gw): Support border-image-outset
-                                outset: SideOffsets2D::zero(),
-                                repeat_horizontal: border_image_repeat.0.to_layout(),
-                                repeat_vertical: border_image_repeat.1.to_layout(),
-                            }),
-                        })));
-                    }
-                }
-            },
+                    )
+                })
+                .and_then(|image| build_image_border_details(image, border_style_struct)),
+        };
+        if let Some(details) = details {
+            state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
+                base,
+                border_widths: border.to_physical(style.writing_mode).to_layout(),
+                details,
+            })));
         }
     }
 
@@ -1531,10 +1507,7 @@ impl FragmentDisplayListBuilding for Fragment {
         // absolute bounds.
         let mut bounds = *bounds;
         let offset = width + Au::from(style.get_outline().outline_offset);
-        bounds.origin.x = bounds.origin.x - offset;
-        bounds.origin.y = bounds.origin.y - offset;
-        bounds.size.width = bounds.size.width + offset + offset;
-        bounds.size.height = bounds.size.height + offset + offset;
+        bounds = bounds.inflate(offset, offset);
 
         // Append the outline to the display list.
         let color = style
@@ -1549,7 +1522,7 @@ impl FragmentDisplayListBuilding for Fragment {
         );
         state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
             base: base,
-            border_widths: SideOffsets2D::new_all_same(width),
+            border_widths: SideOffsets2D::new_all_same(width).to_layout(),
             details: BorderDetails::Normal(simple_normal_border(color, outline_style.to_layout())),
         })));
     }
@@ -1576,7 +1549,7 @@ impl FragmentDisplayListBuilding for Fragment {
         );
         state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
             base: base,
-            border_widths: SideOffsets2D::new_all_same(Au::from_px(1)),
+            border_widths: SideOffsets2D::new_all_same(Au::from_px(1)).to_layout(),
             details: BorderDetails::Normal(simple_normal_border(
                 ColorF::rgb(0, 0, 200),
                 webrender_api::BorderStyle::Solid,
@@ -1623,7 +1596,7 @@ impl FragmentDisplayListBuilding for Fragment {
         );
         state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
             base: base,
-            border_widths: SideOffsets2D::new_all_same(Au::from_px(1)),
+            border_widths: SideOffsets2D::new_all_same(Au::from_px(1)).to_layout(),
             details: BorderDetails::Normal(simple_normal_border(
                 ColorF::rgb(0, 0, 200),
                 webrender_api::BorderStyle::Solid,
@@ -2084,9 +2057,9 @@ impl FragmentDisplayListBuilding for Fragment {
 
         // Create the filter pipeline.
         let effects = self.style().get_effects();
-        let mut filters = effects.filter.0.clone();
+        let mut filters: Vec<FilterOp> = effects.filter.0.iter().map(ToLayout::to_layout).collect();
         if effects.opacity != 1.0 {
-            filters.push(Filter::Opacity(effects.opacity.into()))
+            filters.push(FilterOp::Opacity(effects.opacity.into(), effects.opacity));
         }
 
         StackingContext::new(
@@ -2095,7 +2068,7 @@ impl FragmentDisplayListBuilding for Fragment {
             &border_box,
             &overflow,
             self.effective_z_index(),
-            filters.into(),
+            filters,
             self.style().get_effects().mix_blend_mode.to_layout(),
             self.transform_matrix(&border_box),
             self.style().get_used_transform_style().to_layout(),
@@ -2171,8 +2144,7 @@ impl FragmentDisplayListBuilding for Fragment {
         }
 
         // Create display items for text decorations.
-        let text_decorations =
-            self.style().get_inheritedtext().text_decorations_in_effect;
+        let text_decorations = self.style().get_inheritedtext().text_decorations_in_effect;
 
         let stacking_relative_content_box = LogicalRect::from_physical(
             self.style.writing_mode,
@@ -2697,7 +2669,7 @@ impl BlockFlowDisplayListBuilding for BlockFlow {
             id: None,
             parent_index: self.clipping_and_scrolling().scrolling,
             clip: ClippingRegion::from_rect(border_box),
-            content_rect: Rect::zero(),
+            content_rect: LayoutRect::zero(),
             node_type: ClipScrollNodeType::StickyFrame(sticky_frame_data),
         });
 
@@ -2755,7 +2727,7 @@ impl BlockFlowDisplayListBuilding for BlockFlow {
             id: Some(new_clip_scroll_node_id),
             parent_index: self.clipping_and_scrolling().scrolling,
             clip: clip,
-            content_rect: Rect::new(content_box.origin, content_size),
+            content_rect: Rect::new(content_box.origin, content_size).to_layout(),
             node_type: ClipScrollNodeType::ScrollFrame(sensitivity),
         });
 
@@ -2808,7 +2780,7 @@ impl BlockFlowDisplayListBuilding for BlockFlow {
             id: None,
             parent_index: self.clipping_and_scrolling().scrolling,
             clip: ClippingRegion::from_rect(&clip_rect),
-            content_rect: Rect::zero(), // content_rect isn't important for clips.
+            content_rect: LayoutRect::zero(), // content_rect isn't important for clips.
             node_type: ClipScrollNodeType::Clip,
         });
 
@@ -3148,7 +3120,7 @@ impl BaseFlowDisplayListBuilding for BaseFlow {
         );
         state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
             base: base,
-            border_widths: SideOffsets2D::new_all_same(Au::from_px(2)),
+            border_widths: SideOffsets2D::new_all_same(Au::from_px(2)).to_layout(),
             details: BorderDetails::Normal(simple_normal_border(
                 color,
                 webrender_api::BorderStyle::Solid,
diff --git a/servo/components/layout/display_list/webrender_helpers.rs b/servo/components/layout/display_list/webrender_helpers.rs
index b08c1f0cf474..a4d221f3d12f 100644
--- a/servo/components/layout/display_list/webrender_helpers.rs
+++ b/servo/components/layout/display_list/webrender_helpers.rs
@@ -77,7 +77,7 @@ impl WebRenderDisplayListConverter for DisplayList {
 impl WebRenderDisplayItemConverter for DisplayItem {
     fn prim_info(&self) -> webrender_api::LayoutPrimitiveInfo {
         let tag = match self.base().metadata.pointing {
-            Some(cursor) => Some((self.base().metadata.node.0 as u64, cursor as u16)),
+            Some(cursor) => Some((self.base().metadata.node.0 as u64, cursor)),
             None => None,
         };
         webrender_api::LayoutPrimitiveInfo {
@@ -173,29 +173,11 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                 }
             },
             DisplayItem::Border(ref item) => {
-                let widths = item.border_widths.to_layout();
-
                 let details = match item.details {
                     BorderDetails::Normal(ref border) => {
                         webrender_api::BorderDetails::Normal(*border)
                     },
-                    BorderDetails::Image(ref image) => match image.image.key {
-                        None => return,
-                        Some(key) => {
-                            webrender_api::BorderDetails::Image(webrender_api::ImageBorder {
-                                image_key: key,
-                                patch: webrender_api::NinePatchDescriptor {
-                                    width: image.image.width,
-                                    height: image.image.height,
-                                    slice: image.slice,
-                                },
-                                fill: image.fill,
-                                outset: image.outset,
-                                repeat_horizontal: image.repeat_horizontal,
-                                repeat_vertical: image.repeat_vertical,
-                            })
-                        },
-                    },
+                    BorderDetails::Image(ref image) => webrender_api::BorderDetails::Image(*image),
                     BorderDetails::Gradient(ref gradient) => {
                         webrender_api::BorderDetails::Gradient(webrender_api::GradientBorder {
                             gradient: builder.create_gradient(
@@ -222,7 +204,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                     },
                 };
 
-                builder.push_border(&self.prim_info(), widths, details);
+                builder.push_border(&self.prim_info(), item.border_widths, details);
             },
             DisplayItem::Gradient(ref item) => {
                 let gradient = builder.create_gradient(
@@ -265,7 +247,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                     item.color,
                     item.blur_radius,
                     item.spread_radius,
-                    item.border_radius.to_border_radius(),
+                    item.border_radius,
                     item.clip_mode,
                 );
             },
@@ -303,11 +285,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                     stacking_context.transform_style,
                     perspective,
                     stacking_context.mix_blend_mode,
-                    stacking_context
-                        .filters
-                        .iter()
-                        .map(ToLayout::to_layout)
-                        .collect(),
+                    stacking_context.filters.clone(),
                 );
             },
             DisplayItem::PopStackingContext(_) => builder.pop_stacking_context(),
@@ -328,7 +306,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                         .define_scroll_frame_with_parent(
                             node.id,
                             parent_id,
-                            node.content_rect.to_layout(),
+                            node.content_rect,
                             node.clip.main.to_layout(),
                             node.clip.get_complex_clips(),
                             None,
diff --git a/servo/components/malloc_size_of/lib.rs b/servo/components/malloc_size_of/lib.rs
index 6a7e0255cc5a..9609f9890551 100644
--- a/servo/components/malloc_size_of/lib.rs
+++ b/servo/components/malloc_size_of/lib.rs
@@ -714,10 +714,13 @@ impl MallocSizeOf for url::Host {
         }
     }
 }
-
+#[cfg(feature = "servo")]
+malloc_size_of_is_0!(webrender_api::BorderRadius);
 #[cfg(feature = "servo")]
 malloc_size_of_is_0!(webrender_api::BorderStyle);
 #[cfg(feature = "servo")]
+malloc_size_of_is_0!(webrender_api::BorderWidths);
+#[cfg(feature = "servo")]
 malloc_size_of_is_0!(webrender_api::BoxShadowClipMode);
 #[cfg(feature = "servo")]
 malloc_size_of_is_0!(webrender_api::ClipAndScrollInfo);
@@ -728,8 +731,12 @@ malloc_size_of_is_0!(webrender_api::ColorF);
 #[cfg(feature = "servo")]
 malloc_size_of_is_0!(webrender_api::ExtendMode);
 #[cfg(feature = "servo")]
+malloc_size_of_is_0!(webrender_api::FilterOp);
+#[cfg(feature = "servo")]
 malloc_size_of_is_0!(webrender_api::GradientStop);
 #[cfg(feature = "servo")]
+malloc_size_of_is_0!(webrender_api::ImageBorder);
+#[cfg(feature = "servo")]
 malloc_size_of_is_0!(webrender_api::ImageKey);
 #[cfg(feature = "servo")]
 malloc_size_of_is_0!(webrender_api::ImageRendering);
diff --git a/servo/components/script/dom/create.rs b/servo/components/script/dom/create.rs
index 49661e4b5bf3..64116663a848 100644
--- a/servo/components/script/dom/create.rs
+++ b/servo/components/script/dom/create.rs
@@ -54,6 +54,7 @@ use dom::htmloptionelement::HTMLOptionElement;
 use dom::htmloutputelement::HTMLOutputElement;
 use dom::htmlparagraphelement::HTMLParagraphElement;
 use dom::htmlparamelement::HTMLParamElement;
+use dom::htmlpictureelement::HTMLPictureElement;
 use dom::htmlpreelement::HTMLPreElement;
 use dom::htmlprogresselement::HTMLProgressElement;
 use dom::htmlquoteelement::HTMLQuoteElement;
@@ -309,6 +310,7 @@ pub fn create_native_html_element(
         local_name!("output")     => make!(HTMLOutputElement),
         local_name!("p")          => make!(HTMLParagraphElement),
         local_name!("param")      => make!(HTMLParamElement),
+        local_name!("picture")    => make!(HTMLPictureElement),
         local_name!("plaintext")  => make!(HTMLPreElement),
         local_name!("pre")        => make!(HTMLPreElement),
         local_name!("progress")   => make!(HTMLProgressElement),
diff --git a/servo/components/script/dom/htmlpictureelement.rs b/servo/components/script/dom/htmlpictureelement.rs
new file mode 100644
index 000000000000..cf5154a47a19
--- /dev/null
+++ b/servo/components/script/dom/htmlpictureelement.rs
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use dom::bindings::codegen::Bindings::HTMLPictureElementBinding;
+use dom::bindings::root::DomRoot;
+use dom::document::Document;
+use dom::htmlelement::HTMLElement;
+use dom::node::Node;
+use dom_struct::dom_struct;
+use html5ever::{LocalName, Prefix};
+
+#[dom_struct]
+pub struct HTMLPictureElement {
+    htmlelement: HTMLElement,
+}
+
+impl HTMLPictureElement {
+    fn new_inherited(local_name: LocalName,
+                     prefix: Option<Prefix>,
+                     document: &Document) -> HTMLPictureElement {
+        HTMLPictureElement {
+            htmlelement:
+                HTMLElement::new_inherited(local_name, prefix, document)
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    pub fn new(local_name: LocalName,
+               prefix: Option<Prefix>,
+               document: &Document) -> DomRoot<HTMLPictureElement> {
+        Node::reflect_node(Box::new(HTMLPictureElement::new_inherited(local_name, prefix, document)),
+                           document,
+                           HTMLPictureElementBinding::Wrap)
+    }
+}
diff --git a/servo/components/script/dom/mod.rs b/servo/components/script/dom/mod.rs
index cf10f1e4752a..78f78cbed756 100644
--- a/servo/components/script/dom/mod.rs
+++ b/servo/components/script/dom/mod.rs
@@ -348,6 +348,7 @@ pub mod htmloptionscollection;
 pub mod htmloutputelement;
 pub mod htmlparagraphelement;
 pub mod htmlparamelement;
+pub mod htmlpictureelement;
 pub mod htmlpreelement;
 pub mod htmlprogresselement;
 pub mod htmlquoteelement;
diff --git a/servo/components/script/dom/webidls/HTMLPictureElement.webidl b/servo/components/script/dom/webidls/HTMLPictureElement.webidl
new file mode 100644
index 000000000000..4886ebcd68e1
--- /dev/null
+++ b/servo/components/script/dom/webidls/HTMLPictureElement.webidl
@@ -0,0 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#htmlpictureelement
+[HTMLConstructor]
+interface HTMLPictureElement : HTMLElement {};
diff --git a/taskcluster/ci/source-test/mozlint.yml b/taskcluster/ci/source-test/mozlint.yml
index 37174bc3e556..cbeb3980a765 100644
--- a/taskcluster/ci/source-test/mozlint.yml
+++ b/taskcluster/ci/source-test/mozlint.yml
@@ -132,3 +132,14 @@ yaml:
             - '**/*.yml'
             - '**/*.yaml'
             - '**/.ymllint'
+
+shellcheck:
+    description: shellcheck run over the gecko codebase
+    platform: lint/opt
+    treeherder:
+        symbol: shell
+    run:
+        mach: lint -l shellcheck -f treeherder
+    when:
+        files-changed:
+            - '**/*.sh'
diff --git a/taskcluster/ci/test/test-platforms.yml b/taskcluster/ci/test/test-platforms.yml
index a92e603445bc..3a5dd172a595 100644
--- a/taskcluster/ci/test/test-platforms.yml
+++ b/taskcluster/ci/test/test-platforms.yml
@@ -62,6 +62,7 @@ linux64-nightly/opt:
         - opt-only-tests
         - desktop-screenshot-capture
         - awsy
+        - linux-talos-profiling
 linux64-devedition/opt:
     build-platform: linux64-devedition-nightly/opt
     test-sets:
diff --git a/taskcluster/ci/test/test-sets.yml b/taskcluster/ci/test/test-sets.yml
index baf216bb3e0f..37e351bece1f 100644
--- a/taskcluster/ci/test/test-sets.yml
+++ b/taskcluster/ci/test/test-sets.yml
@@ -135,6 +135,22 @@ linux-qr-tests:
     - reftest
     - xpcshell
 
+linux-talos-profiling:
+    - talos-chrome-profiling
+    - talos-dromaeojs-profiling
+    - talos-g1-profiling
+    - talos-g2-profiling
+    - talos-g3-profiling
+    - talos-g4-profiling
+    - talos-g5-profiling
+    - talos-other-profiling
+    - talos-perf-reftest-profiling
+    - talos-perf-reftest-singletons-profiling
+    - talos-speedometer-profiling
+    - talos-svgr-profiling
+    - talos-tp5o-profiling
+    - talos-tp6-profiling
+
 windows-qr-tests:
     - crashtest
     - mochitest-gpu
@@ -297,6 +313,7 @@ macosx64-talos-profiling:
     - talos-perf-reftest-singletons-profiling
     - talos-speedometer-profiling
     - talos-svgr-profiling
+    - talos-tp5o-profiling
     - talos-tp6-profiling
 
 linux32-tests:
diff --git a/taskcluster/docker/firefox-snap/runme.sh b/taskcluster/docker/firefox-snap/runme.sh
index 203b42c3ba6f..7cf375f865ad 100755
--- a/taskcluster/docker/firefox-snap/runme.sh
+++ b/taskcluster/docker/firefox-snap/runme.sh
@@ -47,7 +47,7 @@ for locale in $locales; do
 done
 
 # Generate snapcraft manifest
-sed -e "s/@VERSION@/${VERSION}/g" -e "s/@BUILD_NUMBER@/${BUILD_NUMBER}/g" snapcraft.yaml.in > ${WORKSPACE}/snapcraft.yaml
+sed -e "s/@VERSION@/${VERSION}/g" -e "s/@BUILD_NUMBER@/${BUILD_NUMBER}/g" snapcraft.yaml.in > "${WORKSPACE}/snapcraft.yaml"
 cd "${WORKSPACE}"
 snapcraft
 
diff --git a/taskcluster/docker/image_builder/build-image.sh b/taskcluster/docker/image_builder/build-image.sh
index d99a414ba73e..7da8da97c13b 100755
--- a/taskcluster/docker/image_builder/build-image.sh
+++ b/taskcluster/docker/image_builder/build-image.sh
@@ -23,6 +23,8 @@ test -n "$IMAGE_NAME" || raise_error "IMAGE_NAME must be provided."
 # proxy socket that the worker user can use.
 export DOCKER_SOCKET=/var/run/docker.proxy
 socat UNIX-LISTEN:$DOCKER_SOCKET,fork,group=worker,mode=0775 UNIX-CLIENT:/var/run/docker.sock </dev/null &
+# Disable check until new version is tested.
+# shellcheck disable=SC2064
 trap "kill $!" EXIT
 
 LOAD_COMMAND=
diff --git a/taskcluster/docker/recipes/debian-build-system-setup.sh b/taskcluster/docker/recipes/debian-build-system-setup.sh
index 03acb5ec6a6a..de4e04cee7b1 100644
--- a/taskcluster/docker/recipes/debian-build-system-setup.sh
+++ b/taskcluster/docker/recipes/debian-build-system-setup.sh
@@ -5,9 +5,7 @@
 
 cd /setup || exit
 
-# shellcheck source=taskcluster/docker/recipes/common.sh
 . /setup/common.sh
-# shellcheck source=taskcluster/docker/recipes/install-mercurial.sh
 . /setup/install-mercurial.sh
 
 rm -rf /setup
diff --git a/taskcluster/docker/recipes/ubuntu1604-test-system-setup.sh b/taskcluster/docker/recipes/ubuntu1604-test-system-setup.sh
index e173ff343eaa..fd6bb6ac96b0 100644
--- a/taskcluster/docker/recipes/ubuntu1604-test-system-setup.sh
+++ b/taskcluster/docker/recipes/ubuntu1604-test-system-setup.sh
@@ -91,16 +91,13 @@ apt-get install -y -f "${apt_packages[@]}"
 
 dpkg-reconfigure locales
 
-# shellcheck source=taskcluster/docker/recipes/common.sh
 . /setup/common.sh
-# shellcheck source=taskcluster/docker/recipes/install-mercurial.sh
 . /setup/install-mercurial.sh
 
 pip install --upgrade pip
 
 pip install virtualenv
 
-# shellcheck source=taskcluster/docker/recipes/install-node.sh
 . /setup/install-node.sh
 
 # Install custom-built Debian packages.  These come from a set of repositories
diff --git a/testing/talos/talos.json b/testing/talos/talos.json
index 5a2376aa85f0..72a14f4ec641 100644
--- a/testing/talos/talos.json
+++ b/testing/talos/talos.json
@@ -3,6 +3,10 @@
         "chromez-e10s": {
             "tests": ["tresize"]
         },
+        "chromez-profiling-e10s": {
+            "talos_options": ["--geckoProfile"],
+            "tests": ["tresize"]
+        },
         "chromez-stylo-disabled-e10s": {
             "talos_options": ["--disable-stylo"],
             "tests": ["tresize"]
@@ -10,6 +14,10 @@
         "dromaeojs-e10s": {
             "tests": ["dromaeo_css", "kraken"]
         },
+        "dromaeojs-profiling-e10s": {
+            "talos_options": ["--geckoProfile"],
+            "tests": ["dromaeo_css", "kraken"]
+        },
         "dromaeojs-stylo-disabled-e10s": {
             "talos_options": ["--disable-stylo"],
             "tests": ["dromaeo_css", "kraken"]
@@ -17,6 +25,10 @@
         "other-e10s": {
             "tests": ["a11yr", "ts_paint", "tpaint", "sessionrestore", "sessionrestore_many_windows", "sessionrestore_no_auto_restore", "tabpaint", "cpstartup"]
         },
+        "other-profiling-e10s": {
+            "talos_options": ["--geckoProfile"],
+            "tests": ["a11yr", "ts_paint", "tpaint", "sessionrestore", "sessionrestore_many_windows", "sessionrestore_no_auto_restore", "tabpaint", "cpstartup"]
+        },
         "other-stylo-disabled-e10s": {
             "talos_options": ["--disable-stylo"],
             "tests": ["a11yr", "ts_paint", "tpaint", "sessionrestore", "sessionrestore_many_windows", "sessionrestore_no_auto_restore", "tabpaint", "cpstartup"]
@@ -25,6 +37,11 @@
             "tests": ["tp5o_scroll", "glterrain"],
             "pagesets_name": "tp5n.zip"
         },
+        "g1-profiling-e10s": {
+            "tests": ["tp5o_scroll", "glterrain"],
+            "talos_options": ["--geckoProfile"],
+            "pagesets_name": "tp5n.zip"
+        },
         "g1-stylo-disabled-e10s": {
             "tests": ["tp5o_scroll", "glterrain"],
             "talos_options": ["--disable-stylo"],
@@ -34,6 +51,11 @@
             "tests": ["damp", "tps"],
             "pagesets_name": "tp5n.zip"
         },
+        "g2-profiling-e10s": {
+            "tests": ["damp", "tps"],
+            "talos_options": ["--geckoProfile"],
+            "pagesets_name": "tp5n.zip"
+        },
         "g2-stylo-disabled-e10s": {
             "tests": ["damp", "tps"],
             "talos_options": ["--disable-stylo"],
@@ -42,6 +64,10 @@
         "g3-e10s": {
             "tests": ["dromaeo_dom"]
         },
+        "g3-profiling-e10s": {
+            "tests": ["dromaeo_dom"],
+            "talos_options": ["--geckoProfile"]
+        },
         "g3-stylo-disabled-e10s": {
             "tests": ["dromaeo_dom"],
             "talos_options": ["--disable-stylo"]
@@ -49,6 +75,10 @@
         "g4-e10s": {
             "tests": ["basic_compositor_video", "glvideo", "displaylist_mutate", "rasterflood_svg", "rasterflood_gradient"]
         },
+        "g4-profiling-e10s": {
+            "tests": ["basic_compositor_video", "glvideo"],
+            "talos_options": ["--geckoProfile"]
+        },
         "g4-stylo-disabled-e10s": {
             "tests": ["basic_compositor_video", "glvideo"],
             "talos_options": ["--disable-stylo"]
@@ -57,6 +87,11 @@
             "tests": ["ts_paint_webext", "tp5o_webext"],
             "pagesets_name": "tp5n.zip"
         },
+        "g5-profiling-e10s": {
+            "tests": ["ts_paint_webext", "tp5o_webext"],
+            "talos_options": ["--geckoProfile"],
+            "pagesets_name": "tp5n.zip"
+        },
         "g5-stylo-disabled-e10s": {
             "tests": ["ts_paint_webext", "tp5o_webext"],
             "talos_options": ["--disable-stylo"],
@@ -65,6 +100,10 @@
         "svgr-e10s": {
             "tests": ["tsvgx", "tsvgr_opacity", "tart", "tscrollx", "tsvg_static"]
         },
+        "svgr-profiling-e10s": {
+            "tests": ["tsvgx", "tsvgr_opacity", "tart", "tscrollx", "tsvg_static"],
+            "talos_options": ["--geckoProfile"]
+        },
         "svgr-stylo-disabled-e10s": {
             "tests": ["tsvgx", "tsvgr_opacity", "tart", "tscrollx", "tsvg_static"],
             "talos_options": ["--disable-stylo"]
@@ -72,6 +111,10 @@
         "perf-reftest-e10s": {
             "tests": ["perf_reftest"]
         },
+        "perf-reftest-profiling-e10s": {
+            "tests": ["perf_reftest"],
+            "talos_options": ["--geckoProfile"]
+        },
         "perf-reftest-stylo-disabled-e10s": {
             "tests": ["perf_reftest"],
             "talos_options": ["--disable-stylo"]
@@ -79,6 +122,10 @@
         "perf-reftest-singletons-e10s": {
             "tests": ["perf_reftest_singletons"]
         },
+        "perf-reftest-singletons-profiling-e10s": {
+            "tests": ["perf_reftest_singletons"],
+            "talos_options": ["--geckoProfile"]
+        },
         "perf-reftest-singletons-stylo-disabled-e10s": {
             "tests": ["perf_reftest_singletons"],
             "talos_options": ["--disable-stylo"]
@@ -86,6 +133,10 @@
         "speedometer-e10s": {
             "tests": ["speedometer", "stylebench"]
         },
+        "speedometer-profiling-e10s": {
+            "talos_options": ["--geckoProfile"],
+            "tests": ["speedometer"]
+        },
         "speedometer-stylo-disabled-e10s": {
             "talos_options": ["--disable-stylo"],
             "tests": ["speedometer"]
@@ -94,6 +145,11 @@
             "tests": ["tp5o"],
             "pagesets_name": "tp5n.zip"
         },
+        "tp5o-profiling-e10s": {
+            "tests": ["tp5o"],
+            "pagesets_name": "tp5n.zip",
+            "talos_options": ["--geckoProfile"]
+        },
         "tp5o-stylo-disabled-e10s": {
             "tests": ["tp5o"],
             "pagesets_name": "tp5n.zip",
@@ -127,6 +183,18 @@
                 "--firstNonBlankPaint"
             ]
         },
+        "tp6-profiling-e10s": {
+            "tests": ["tp6_google", "tp6_youtube", "tp6_amazon", "tp6_facebook"],
+            "mitmproxy_release_bin_osx": "mitmproxy-2.0.2-osx.tar.gz",
+            "mitmproxy_release_bin_linux64": "mitmproxy-2.0.2-linux.tar.gz",
+            "mitmproxy_recording_set": "mitmproxy-recording-set-win10.zip",
+            "talos_options": [
+                "--geckoProfile",
+                "--mitmproxy",
+                "mitmproxy-recording-google.mp mitmproxy-recording-youtube.mp mitmproxy-recording-amazon.mp mitmproxy-recording-facebook.mp",
+                "--firstNonBlankPaint"
+            ]
+        },
         "tp6-stylo-disabled-e10s": {
             "tests": ["tp6_google", "tp6_youtube", "tp6_amazon", "tp6_facebook"],
             "mitmproxy_release_bin_osx": "mitmproxy-2.0.2-osx.tar.gz",
diff --git a/toolkit/library/gtest/rust/Cargo.lock b/toolkit/library/gtest/rust/Cargo.lock
index 9ba9b0a89064..f410dd2d082b 100644
--- a/toolkit/library/gtest/rust/Cargo.lock
+++ b/toolkit/library/gtest/rust/Cargo.lock
@@ -45,7 +45,7 @@ dependencies = [
 
 [[package]]
 name = "audioipc"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
  "bincode 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -68,7 +68,7 @@ dependencies = [
 name = "audioipc-client"
 version = "0.2.0"
 dependencies = [
- "audioipc 0.2.0",
+ "audioipc 0.2.1",
  "cubeb-backend 0.2.0",
  "cubeb-core 0.1.0",
  "futures 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -81,11 +81,11 @@ dependencies = [
 
 [[package]]
 name = "audioipc-server"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
- "audioipc 0.2.0",
+ "audioipc 0.2.1",
  "bytes 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "cubeb 0.3.1",
+ "cubeb 0.3.2",
  "cubeb-core 0.1.0",
  "error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -316,7 +316,7 @@ dependencies = [
 
 [[package]]
 name = "cubeb"
-version = "0.3.1"
+version = "0.3.2"
 dependencies = [
  "cubeb-core 0.1.0",
  "libcubeb-sys 0.1.0",
@@ -582,9 +582,9 @@ name = "gkrust-shared"
 version = "0.1.0"
 dependencies = [
  "audioipc-client 0.2.0",
- "audioipc-server 0.2.0",
+ "audioipc-server 0.2.1",
  "cose-c 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "cubeb 0.3.1",
+ "cubeb 0.3.2",
  "cubeb-backend 0.2.0",
  "cubeb-core 0.1.0",
  "cubeb-pulse 0.0.2",
diff --git a/toolkit/library/rust/Cargo.lock b/toolkit/library/rust/Cargo.lock
index af3ac6c2cb6c..fb4f3ad1ed5d 100644
--- a/toolkit/library/rust/Cargo.lock
+++ b/toolkit/library/rust/Cargo.lock
@@ -45,7 +45,7 @@ dependencies = [
 
 [[package]]
 name = "audioipc"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
  "bincode 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -68,7 +68,7 @@ dependencies = [
 name = "audioipc-client"
 version = "0.2.0"
 dependencies = [
- "audioipc 0.2.0",
+ "audioipc 0.2.1",
  "cubeb-backend 0.2.0",
  "cubeb-core 0.1.0",
  "futures 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -81,11 +81,11 @@ dependencies = [
 
 [[package]]
 name = "audioipc-server"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
- "audioipc 0.2.0",
+ "audioipc 0.2.1",
  "bytes 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "cubeb 0.3.1",
+ "cubeb 0.3.2",
  "cubeb-core 0.1.0",
  "error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -316,7 +316,7 @@ dependencies = [
 
 [[package]]
 name = "cubeb"
-version = "0.3.1"
+version = "0.3.2"
 dependencies = [
  "cubeb-core 0.1.0",
  "libcubeb-sys 0.1.0",
@@ -580,9 +580,9 @@ name = "gkrust-shared"
 version = "0.1.0"
 dependencies = [
  "audioipc-client 0.2.0",
- "audioipc-server 0.2.0",
+ "audioipc-server 0.2.1",
  "cose-c 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "cubeb 0.3.1",
+ "cubeb 0.3.2",
  "cubeb-backend 0.2.0",
  "cubeb-core 0.1.0",
  "cubeb-pulse 0.0.2",
diff --git a/toolkit/themes/shared/close-icon.inc.css b/toolkit/themes/shared/close-icon.inc.css
index 2958b62f0b61..3698a4ea4c73 100644
--- a/toolkit/themes/shared/close-icon.inc.css
+++ b/toolkit/themes/shared/close-icon.inc.css
@@ -19,7 +19,6 @@
   fill-opacity: 0.2;
 }
 
-image.close-icon,
 .close-icon > .button-icon,
 .close-icon > .button-box > .button-icon,
 .close-icon > .toolbarbutton-icon {
diff --git a/tools/lint/shell/__init__.py b/tools/lint/shell/__init__.py
index bf639a8ed799..2e82a76ecbd3 100644
--- a/tools/lint/shell/__init__.py
+++ b/tools/lint/shell/__init__.py
@@ -155,7 +155,7 @@ def lint(paths, config, **lintargs):
 
     files = find_shell_scripts(config, paths)
 
-    base_command = [binary, '-x', '-f', 'json']
+    base_command = [binary, '-f', 'json']
     if config.get('excludecodes'):
         base_command.extend(['-e', ','.join(config.get('excludecodes'))])
 
diff --git a/tools/lint/shellcheck.yml b/tools/lint/shellcheck.yml
index 1ce72e5906a7..df93627aa6a8 100644
--- a/tools/lint/shellcheck.yml
+++ b/tools/lint/shellcheck.yml
@@ -2,11 +2,11 @@
 shellcheck:
     description: Shell script linter
     include:
-        - taskcluster/docker/funsize-update-generator/scripts/
+        - taskcluster/docker/
     exclude: []
     # 1090: https://github.com/koalaman/shellcheck/wiki/SC1090
     # 'Can't follow a non-constant source'
     extensions: ['sh']
-    excludecodes: ['1090']
+    excludecodes: ['1090', '1091']
     type: external
     payload: shell:lint
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index 448658a46d5f..d0ef56f1659f 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -6887,7 +6887,13 @@ nsWindow::GetCSDSupportLevel() {
         } else if (strstr(currentDesktop, "LXQt") != nullptr) {
             sCSDSupportLevel = CSD_SUPPORT_FULL;
         } else {
+// Release or beta builds are not supposed to be broken
+// so disable titlebar rendering on untested/unknown systems.
+#if defined(RELEASE_OR_BETA)
+            sCSDSupportLevel = CSD_SUPPORT_NONE;
+#else
             sCSDSupportLevel = CSD_SUPPORT_FLAT;
+#endif
         }
     } else {
         sCSDSupportLevel = CSD_SUPPORT_NONE;