Schedule bitmap animation timers on the compositor task runner.

third_party/WebKit/Source/platform/scheduler/child/web_scheduler.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_WEB_SCHEDULER_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_WEB_SCHEDULER_H_
 
 #include "platform/scheduler/renderer/web_view_scheduler.h"
 #include "public/platform/WebString.h"
 #include "public/platform/WebThread.h"
@@ skipping 54 matching lines @@
   // run earlier than it normally would.
   virtual void PostNonNestableIdleTask(const WebTraceLocation&,
                                        WebThread::IdleTask*) = 0;
 
   // Returns a WebTaskRunner for loading tasks. Can be called from any thread.
   virtual WebTaskRunner* LoadingTaskRunner() = 0;
 
   // Returns a WebTaskRunner for timer tasks. Can be called from any thread.
   virtual WebTaskRunner* TimerTaskRunner() = 0;
 
+  // Returns a WebTaskRunner for compositor tasks.

[Sami, 2017/05/04 00:33:38]

Could add a bit more scary explanation here how this is only meant for specific
animation and rendering related tasks and should not be used generally?

[Dan Elphick, 2017/05/04 16:47:15]

Done.

+  virtual WebTaskRunner* CompositorTaskRunner() = 0;
+
   // Creates a new WebViewScheduler for a given WebView. Must be called from
   // the associated WebThread.
   virtual std::unique_ptr<WebViewScheduler> CreateWebViewScheduler(
       InterventionReporter*,
       WebViewScheduler::WebViewSchedulerSettings*) = 0;
 
   // Suspends the timer queue and increments the timer queue suspension count.
   // May only be called from the main thread.
   virtual void SuspendTimerQueue() = 0;
 
@@ skipping 16 matching lines @@
 
   void PostIdleTask(const WebTraceLocation&, std::unique_ptr<IdleTask>);
   void PostNonNestableIdleTask(const WebTraceLocation&,
                                std::unique_ptr<IdleTask>);
 #endif
 };
 
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_WEB_SCHEDULER_H_