diff --git a/content/base/src/Element.cpp b/content/base/src/Element.cpp
index 75b13d4f5bb0..f99469faf8a2 100644
--- a/content/base/src/Element.cpp
+++ b/content/base/src/Element.cpp
@@ -73,7 +73,6 @@
 #include "nsLayoutUtils.h"
 #include "nsGkAtoms.h"
 #include "nsContentUtils.h"
-#include "nsIJSContextStack.h"
 
 #include "nsIDOMEventListener.h"
 #include "nsIWebNavigation.h"
diff --git a/content/base/src/EventSource.cpp b/content/base/src/EventSource.cpp
index e4ea6458bd9f..dff04f6583c4 100644
--- a/content/base/src/EventSource.cpp
+++ b/content/base/src/EventSource.cpp
@@ -12,7 +12,6 @@
 #include "nsNetUtil.h"
 #include "nsMimeTypes.h"
 #include "nsDOMMessageEvent.h"
-#include "nsIJSContextStack.h"
 #include "nsIPromptFactory.h"
 #include "nsIWindowWatcher.h"
 #include "nsPresContext.h"
@@ -201,10 +200,8 @@ EventSource::Init(nsISupports* aOwner,
   mWithCredentials = aWithCredentials;
   BindToOwner(ownerWindow);
 
-  nsCOMPtr<nsIJSContextStack> stack =
-    do_GetService("@mozilla.org/js/xpc/ContextStack;1");
-  JSContext* cx = nullptr;
-  if (stack && NS_SUCCEEDED(stack->Peek(&cx)) && cx) {
+  // The conditional here is historical and not necessarily sane.
+  if (JSContext *cx = nsContentUtils::GetCurrentJSContext()) {
     const char *filename;
     if (nsJSUtils::GetCallingLocation(cx, &filename, &mScriptLine)) {
       mScriptFile.AssignASCII(filename);
diff --git a/content/base/src/FragmentOrElement.cpp b/content/base/src/FragmentOrElement.cpp
index 853f9c1fe822..ee55537c961e 100644
--- a/content/base/src/FragmentOrElement.cpp
+++ b/content/base/src/FragmentOrElement.cpp
@@ -72,7 +72,6 @@
 #include "nsLayoutUtils.h"
 #include "nsGkAtoms.h"
 #include "nsContentUtils.h"
-#include "nsIJSContextStack.h"
 
 #include "nsIDOMEventListener.h"
 #include "nsIWebNavigation.h"
diff --git a/content/base/src/WebSocket.cpp b/content/base/src/WebSocket.cpp
index 1552f8937b83..ae1f6362eaeb 100644
--- a/content/base/src/WebSocket.cpp
+++ b/content/base/src/WebSocket.cpp
@@ -32,7 +32,6 @@
 #include "nsIDOMCloseEvent.h"
 #include "nsICryptoHash.h"
 #include "jsdbgapi.h"
-#include "nsIJSContextStack.h"
 #include "nsJSUtils.h"
 #include "nsIScriptError.h"
 #include "nsNetUtil.h"
diff --git a/content/base/src/nsDOMFileReader.cpp b/content/base/src/nsDOMFileReader.cpp
index b0b70a8d70a1..f996a3cd7b4e 100644
--- a/content/base/src/nsDOMFileReader.cpp
+++ b/content/base/src/nsDOMFileReader.cpp
@@ -28,7 +28,6 @@
 #include "nsStreamUtils.h"
 #include "nsXPCOM.h"
 #include "nsIDOMEventListener.h"
-#include "nsIJSContextStack.h"
 #include "nsJSEnvironment.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsCExternalHandlerService.h"
diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index a29c733714f6..c51f31c5f6af 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -124,7 +124,6 @@
 #include "nsDOMCID.h"
 
 #include "jsapi.h"
-#include "nsIJSContextStack.h"
 #include "nsIXPConnect.h"
 #include "nsCycleCollector.h"
 #include "nsCCUncollectableMarker.h"
diff --git a/content/base/src/nsFrameLoader.cpp b/content/base/src/nsFrameLoader.cpp
index 855de66033e2..02d86bc7486f 100644
--- a/content/base/src/nsFrameLoader.cpp
+++ b/content/base/src/nsFrameLoader.cpp
@@ -34,7 +34,6 @@
 #include "nsIBaseWindow.h"
 #include "nsContentUtils.h"
 #include "nsIXPConnect.h"
-#include "nsIJSContextStack.h"
 #include "nsUnicharUtils.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIScriptSecurityManager.h"
diff --git a/content/base/src/nsFrameMessageManager.cpp b/content/base/src/nsFrameMessageManager.cpp
index e0f9f3143d42..45ae0fd9bf8d 100644
--- a/content/base/src/nsFrameMessageManager.cpp
+++ b/content/base/src/nsFrameMessageManager.cpp
@@ -19,7 +19,6 @@
 #include "nsNetUtil.h"
 #include "nsScriptLoader.h"
 #include "nsFrameLoader.h"
-#include "nsIJSContextStack.h"
 #include "nsIXULRuntime.h"
 #include "nsIScriptError.h"
 #include "nsIConsoleService.h"
@@ -630,10 +629,10 @@ nsFrameMessageManager::ReceiveMessage(nsISupports* aTarget,
                                       InfallibleTArray<nsString>* aJSONRetVal,
                                       JSContext* aContext)
 {
-  JSContext* ctx = mContext ? mContext : aContext;
-  if (!ctx) {
-    ctx = nsContentUtils::ThreadJSContextStack()->GetSafeJSContext();
-  }
+  JSContext *cxToUse = mContext ? mContext
+                                : (aContext ? aContext
+                                            : nsContentUtils::GetSafeJSContext());
+  AutoPushJSContext ctx(cxToUse);
   if (mListeners.Length()) {
     nsCOMPtr<nsIAtom> name = do_GetAtom(aMessage);
     MMListenerRemover lr(this);
@@ -976,17 +975,10 @@ void
 nsFrameScriptExecutor::Shutdown()
 {
   if (sCachedScripts) {
-    JSContext* cx = nsContentUtils::ThreadJSContextStack()->GetSafeJSContext();
-    if (cx) {
-#ifdef DEBUG_smaug
-      printf("Will clear cached frame manager scripts!\n");
-#endif
-      JSAutoRequest ar(cx);
-      NS_ASSERTION(sCachedScripts != nullptr, "Need cached scripts");
-      sCachedScripts->Enumerate(CachedScriptUnrooter, cx);
-    } else {
-      NS_WARNING("No context available. Leaking cached scripts!\n");
-    }
+    SafeAutoJSContext cx;
+    JSAutoRequest ar(cx);
+    NS_ASSERTION(sCachedScripts != nullptr, "Need cached scripts");
+    sCachedScripts->Enumerate(CachedScriptUnrooter, cx);
 
     delete sCachedScripts;
     sCachedScripts = nullptr;
diff --git a/content/base/src/nsINode.cpp b/content/base/src/nsINode.cpp
index 08b9541889be..3c3f235dc1b6 100644
--- a/content/base/src/nsINode.cpp
+++ b/content/base/src/nsINode.cpp
@@ -62,7 +62,6 @@
 #include "nsIEditor.h"
 #include "nsIEditorIMESupport.h"
 #include "nsIFrame.h"
-#include "nsIJSContextStack.h"
 #include "nsILinkHandler.h"
 #include "nsINameSpaceManager.h"
 #include "nsINodeInfo.h"
diff --git a/content/base/src/nsInProcessTabChildGlobal.cpp b/content/base/src/nsInProcessTabChildGlobal.cpp
index f4ff2bd4f828..fd0f6c114498 100644
--- a/content/base/src/nsInProcessTabChildGlobal.cpp
+++ b/content/base/src/nsInProcessTabChildGlobal.cpp
@@ -15,7 +15,6 @@
 #include "nsComponentManagerUtils.h"
 #include "nsNetUtil.h"
 #include "nsScriptLoader.h"
-#include "nsIJSContextStack.h"
 #include "nsFrameLoader.h"
 #include "xpcpublic.h"
 #include "nsIMozBrowserFrame.h"
diff --git a/content/base/src/nsObjectLoadingContent.cpp b/content/base/src/nsObjectLoadingContent.cpp
index 4b4e76cc3f38..49d9b9c72265 100644
--- a/content/base/src/nsObjectLoadingContent.cpp
+++ b/content/base/src/nsObjectLoadingContent.cpp
@@ -24,7 +24,6 @@
 #include "nsIPermissionManager.h"
 #include "nsPluginHost.h"
 #include "nsJSNPRuntime.h"
-#include "nsIJSContextStack.h"
 #include "nsIPresShell.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIScriptSecurityManager.h"
diff --git a/content/base/src/nsXMLHttpRequest.cpp b/content/base/src/nsXMLHttpRequest.cpp
index e36112e9018e..6c8851f75992 100644
--- a/content/base/src/nsXMLHttpRequest.cpp
+++ b/content/base/src/nsXMLHttpRequest.cpp
@@ -26,7 +26,6 @@
 #include "nsGUIEvent.h"
 #include "prprf.h"
 #include "nsIDOMEventListener.h"
-#include "nsIJSContextStack.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsWeakPtr.h"
 #include "nsIScriptGlobalObject.h"
diff --git a/content/canvas/src/WebGLContextUtils.cpp b/content/canvas/src/WebGLContextUtils.cpp
index 740522e92d91..89567e7f737b 100644
--- a/content/canvas/src/WebGLContextUtils.cpp
+++ b/content/canvas/src/WebGLContextUtils.cpp
@@ -9,7 +9,6 @@
 
 #include "prprf.h"
 
-#include "nsIJSContextStack.h"
 #include "jsapi.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsServiceManagerUtils.h"
@@ -46,15 +45,12 @@ WebGLContext::GenerateWarning(const char *fmt, va_list ap)
 
     // no need to print to stderr, as JS_ReportWarning takes care of this for us.
 
-    nsCOMPtr<nsIJSContextStack> stack = do_GetService("@mozilla.org/js/xpc/ContextStack;1");
-    JSContext* ccx = nullptr;
-    if (stack && NS_SUCCEEDED(stack->Peek(&ccx)) && ccx) {
-        JS_ReportWarning(ccx, "WebGL: %s", buf);
-        if (!ShouldGenerateWarnings()) {
-            JS_ReportWarning(ccx,
-                "WebGL: No further warnings will be reported for this WebGL context "
-                "(already reported %d warnings)", mAlreadyGeneratedWarnings);
-        }
+    AutoJSContext cx;
+    JS_ReportWarning(cx, "WebGL: %s", buf);
+    if (!ShouldGenerateWarnings()) {
+        JS_ReportWarning(cx,
+            "WebGL: No further warnings will be reported for this WebGL context "
+            "(already reported %d warnings)", mAlreadyGeneratedWarnings);
     }
 }
 
diff --git a/content/events/src/nsDOMEventTargetHelper.cpp b/content/events/src/nsDOMEventTargetHelper.cpp
index be677fa65ce2..d4356e447ea7 100644
--- a/content/events/src/nsDOMEventTargetHelper.cpp
+++ b/content/events/src/nsDOMEventTargetHelper.cpp
@@ -8,7 +8,6 @@
 #include "nsEventDispatcher.h"
 #include "nsGUIEvent.h"
 #include "nsIDocument.h"
-#include "nsIJSContextStack.h"
 #include "nsDOMJSUtils.h"
 #include "prprf.h"
 #include "nsGlobalWindow.h"
diff --git a/content/events/src/nsEventListenerManager.cpp b/content/events/src/nsEventListenerManager.cpp
index b7d08dabf762..969793d4b23c 100644
--- a/content/events/src/nsEventListenerManager.cpp
+++ b/content/events/src/nsEventListenerManager.cpp
@@ -32,7 +32,6 @@
 #include "nsIServiceManager.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsError.h"
-#include "nsIJSContextStack.h"
 #include "nsIDocument.h"
 #include "nsIPresShell.h"
 #include "nsMutationEvent.h"
diff --git a/content/events/src/nsEventListenerService.cpp b/content/events/src/nsEventListenerService.cpp
index 22b9f706879d..4bfb9a15e50f 100644
--- a/content/events/src/nsEventListenerService.cpp
+++ b/content/events/src/nsEventListenerService.cpp
@@ -13,7 +13,6 @@
 #include "nsIDOMWindow.h"
 #include "nsPIDOMWindow.h"
 #include "nsJSUtils.h"
-#include "nsIJSContextStack.h"
 #include "nsGUIEvent.h"
 #include "nsEventDispatcher.h"
 #include "nsIJSEventListener.h"
diff --git a/content/html/content/src/HTMLImageElement.cpp b/content/html/content/src/HTMLImageElement.cpp
index 325b66be3497..848a2f9f3e1c 100644
--- a/content/html/content/src/HTMLImageElement.cpp
+++ b/content/html/content/src/HTMLImageElement.cpp
@@ -35,7 +35,6 @@
 
 #include "nsRuleData.h"
 
-#include "nsIJSContextStack.h"
 #include "nsIDOMHTMLMapElement.h"
 #include "nsEventDispatcher.h"
 
diff --git a/content/html/document/src/nsHTMLDocument.cpp b/content/html/document/src/nsHTMLDocument.cpp
index 2e37901d83ba..f37651a9628e 100644
--- a/content/html/document/src/nsHTMLDocument.cpp
+++ b/content/html/document/src/nsHTMLDocument.cpp
@@ -69,7 +69,6 @@
 #include "nsIDocumentInlines.h"
 #include "nsIDocumentEncoder.h" //for outputting selection
 #include "nsICachingChannel.h"
-#include "nsIJSContextStack.h"
 #include "nsIContentViewer.h"
 #include "nsIWyciwygChannel.h"
 #include "nsIScriptElement.h"
@@ -3323,39 +3322,32 @@ nsHTMLDocument::DoClipboardSecurityCheck(bool aPaste)
 {
   nsresult rv = NS_ERROR_FAILURE;
 
-  nsCOMPtr<nsIJSContextStack> stack =
-    do_GetService("@mozilla.org/js/xpc/ContextStack;1");
+  JSContext *cx = nsContentUtils::GetCurrentJSContext();
+  if (!cx) {
+    return NS_OK;
+  }
+  JSAutoRequest ar(cx);
 
-  if (stack) {
-    JSContext *cx = nullptr;
-    stack->Peek(&cx);
-    if (!cx) {
-      return NS_OK;
+  NS_NAMED_LITERAL_CSTRING(classNameStr, "Clipboard");
+
+  nsIScriptSecurityManager *secMan = nsContentUtils::GetSecurityManager();
+
+  if (aPaste) {
+    if (nsHTMLDocument::sPasteInternal_id == JSID_VOID) {
+      nsHTMLDocument::sPasteInternal_id =
+        INTERNED_STRING_TO_JSID(cx, ::JS_InternString(cx, "paste"));
     }
-
-    JSAutoRequest ar(cx);
-
-    NS_NAMED_LITERAL_CSTRING(classNameStr, "Clipboard");
-
-    nsIScriptSecurityManager *secMan = nsContentUtils::GetSecurityManager();
-
-    if (aPaste) {
-      if (nsHTMLDocument::sPasteInternal_id == JSID_VOID) {
-        nsHTMLDocument::sPasteInternal_id =
-          INTERNED_STRING_TO_JSID(cx, ::JS_InternString(cx, "paste"));
-      }
-      rv = secMan->CheckPropertyAccess(cx, nullptr, classNameStr.get(),
-                                       nsHTMLDocument::sPasteInternal_id,
-                                       nsIXPCSecurityManager::ACCESS_GET_PROPERTY);
-    } else {
-      if (nsHTMLDocument::sCutCopyInternal_id == JSID_VOID) {
-        nsHTMLDocument::sCutCopyInternal_id =
-          INTERNED_STRING_TO_JSID(cx, ::JS_InternString(cx, "cutcopy"));
-      }
-      rv = secMan->CheckPropertyAccess(cx, nullptr, classNameStr.get(),
-                                       nsHTMLDocument::sCutCopyInternal_id,
-                                       nsIXPCSecurityManager::ACCESS_GET_PROPERTY);
+    rv = secMan->CheckPropertyAccess(cx, nullptr, classNameStr.get(),
+                                     nsHTMLDocument::sPasteInternal_id,
+                                     nsIXPCSecurityManager::ACCESS_GET_PROPERTY);
+  } else {
+    if (nsHTMLDocument::sCutCopyInternal_id == JSID_VOID) {
+      nsHTMLDocument::sCutCopyInternal_id =
+        INTERNED_STRING_TO_JSID(cx, ::JS_InternString(cx, "cutcopy"));
     }
+    rv = secMan->CheckPropertyAccess(cx, nullptr, classNameStr.get(),
+                                     nsHTMLDocument::sCutCopyInternal_id,
+                                     nsIXPCSecurityManager::ACCESS_GET_PROPERTY);
   }
   return rv;
 }
diff --git a/content/xml/document/src/XMLDocument.cpp b/content/xml/document/src/XMLDocument.cpp
index 2dfc1328be14..f9232c38e9b6 100644
--- a/content/xml/document/src/XMLDocument.cpp
+++ b/content/xml/document/src/XMLDocument.cpp
@@ -42,7 +42,6 @@
 #include "nsCRT.h"
 #include "nsIAuthPrompt.h"
 #include "nsIScriptGlobalObjectOwner.h"
-#include "nsIJSContextStack.h"
 #include "nsContentCreatorFunctions.h"
 #include "nsContentPolicyUtils.h"
 #include "nsIDOMUserDataHandler.h"