Bug 1300659 P2 Expose a ThrottledEventQueue on TabGroup and nsPIDOMWindow. r=smaug

dom/base/TabGroup.cpp

@@ -1,17 +1,43 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
 #include "mozilla/dom/TabGroup.h"
+
 #include "mozilla/dom/DocGroup.h"
-#include "mozilla/Telemetry.h"
-#include "nsIURI.h"
-#include "nsIEffectiveTLDService.h"
-#include "mozilla/StaticPtr.h"
 #include "mozilla/ClearOnShutdown.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/ThrottledEventQueue.h"
 #include "nsIDocShell.h"
+#include "nsIEffectiveTLDService.h"
+#include "nsIURI.h"
 
 namespace mozilla {
 namespace dom {
 
-TabGroup::TabGroup()
-{}
+static StaticRefPtr<TabGroup> sChromeTabGroup;
+
+TabGroup::TabGroup(bool aIsChrome)
+{
+  // Do not throttle runnables from chrome windows.  In theory we should
+  // not have abuse issues from these windows and many browser chrome
+  // tests have races that fail if we do throttle chrome runnables.
+  if (aIsChrome) {
+    MOZ_ASSERT(!sChromeTabGroup);
+    return;
+  }
+
+  nsCOMPtr<nsIThread> mainThread;
+  NS_GetMainThread(getter_AddRefs(mainThread));
+  MOZ_DIAGNOSTIC_ASSERT(mainThread);
+
+  // This may return nullptr during xpcom shutdown.  This is ok as we
+  // do not guarantee a ThrottledEventQueue will be present.
+  mThrottledEventQueue = ThrottledEventQueue::Create(mainThread);
+}
 
 TabGroup::~TabGroup()
 {
@@ -19,13 +45,11 @@ TabGroup::~TabGroup()
   MOZ_ASSERT(mWindows.IsEmpty());
 }
 
-static StaticRefPtr<TabGroup> sChromeTabGroup;
-
 TabGroup*
 TabGroup::GetChromeTabGroup()
 {
   if (!sChromeTabGroup) {
-    sChromeTabGroup = new TabGroup();
+    sChromeTabGroup = new TabGroup(true /* chrome tab group */);
     ClearOnShutdown(&sChromeTabGroup);
   }
   return sChromeTabGroup;
@@ -130,6 +154,12 @@ TabGroup::GetTopLevelWindows()
   return array;
 }
 
+ThrottledEventQueue*
+TabGroup::GetThrottledEventQueue() const
+{
+  return mThrottledEventQueue;
+}
+
 NS_IMPL_ISUPPORTS(TabGroup, nsISupports)
 
 TabGroup::HashEntry::HashEntry(const nsACString* aKey)

dom/base/TabGroup.h

@@ -16,6 +16,7 @@
 #include "mozilla/RefPtr.h"
 
 namespace mozilla {
+class ThrottledEventQueue;
 namespace dom {
 
 // Two browsing contexts are considered "related" if they are reachable from one
@@ -58,7 +59,7 @@ public:
   static TabGroup*
   GetChromeTabGroup();
 
-  TabGroup();
+  explicit TabGroup(bool aIsChrome = false);
 
   // Get the docgroup for the corresponding doc group key.
   // Returns null if the given key hasn't been seen yet.
@@ -99,10 +100,16 @@ public:
 
   nsTArray<nsPIDOMWindowOuter*> GetTopLevelWindows();
 
+  // Get the event queue that associated windows can use to issue runnables to
+  // the main thread.  This may return nullptr during browser shutdown.
+  ThrottledEventQueue*
+  GetThrottledEventQueue() const;
+
 private:
   ~TabGroup();
   DocGroupMap mDocGroups;
   nsTArray<nsPIDOMWindowOuter*> mWindows;
+  RefPtr<ThrottledEventQueue> mThrottledEventQueue;
 };
 
 } // namespace dom

dom/base/nsGlobalWindow.cpp

@@ -80,6 +80,7 @@
 #include "mozilla/EventStates.h"
 #include "mozilla/MouseEvents.h"
 #include "mozilla/ProcessHangMonitor.h"
+#include "mozilla/ThrottledEventQueue.h"
 #include "AudioChannelService.h"
 #include "nsAboutProtocolUtils.h"
 #include "nsCharTraits.h" // NS_IS_HIGH/LOW_SURROGATE
@@ -9516,6 +9517,18 @@ nsGlobalWindow::UpdateCommands(const nsAString& anAction, nsISelection* aSel, in
   return NS_OK;
 }
 
+ThrottledEventQueue*
+nsGlobalWindow::GetThrottledEventQueue()
+{
+  // We must have an outer to access the TabGroup.
+  nsGlobalWindow* outer = GetOuterWindowInternal();
+  if (!outer) {
+    return nullptr;
+  }
+
+  return TabGroup()->GetThrottledEventQueue();
+}
+
 Selection*
 nsGlobalWindow::GetSelectionOuter()
 {

dom/base/nsGlobalWindow.h

@@ -103,6 +103,7 @@ class nsWindowSizes;
 
 namespace mozilla {
 class DOMEventTargetHelper;
+class ThrottledEventQueue;
 namespace dom {
 class BarProp;
 struct ChannelPixelLayout;
@@ -1157,6 +1158,8 @@ public:
                       nsPIDOMWindowOuter** _retval) override;
   nsresult UpdateCommands(const nsAString& anAction, nsISelection* aSel, int16_t aReason) override;
 
+  mozilla::ThrottledEventQueue* GetThrottledEventQueue() override;
+
   already_AddRefed<nsPIDOMWindowOuter>
     GetContentInternal(mozilla::ErrorResult& aError, bool aUnprivilegedCaller);
   void GetContentOuter(JSContext* aCx,

dom/base/nsPIDOMWindow.h

@@ -40,6 +40,7 @@ class nsXBLPrototypeHandler;
 typedef uint32_t SuspendTypes;
 
 namespace mozilla {
+class ThrottledEventQueue;
 namespace dom {
 class AudioContext;
 class DocGroup;
@@ -581,6 +582,8 @@ public:
 
   mozilla::dom::DocGroup* GetDocGroup();
 
+  virtual mozilla::ThrottledEventQueue* GetThrottledEventQueue() = 0;
+
 protected:
   // The nsPIDOMWindow constructor. The aOuterWindow argument should
   // be null if and only if the created window itself is an outer