Synchronize commits at end of JS task

third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.h

 // Copyright 2015 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 OffscreenCanvas_h
 #define OffscreenCanvas_h
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/ScriptWrappable.h"
@@ skipping 73 matching lines @@
   uint32_t clientId() const { return m_clientId; }
   uint32_t sinkId() const { return m_sinkId; }
 
   void setExecutionContext(ExecutionContext* context) {
     m_executionContext = context;
   }
 
   ScriptPromise commit(RefPtr<StaticBitmapImage>,
                        bool isWebGLSoftwareRendering,
                        ScriptState*);
+  void doCommitAtEndOfTask();
 
   void detachContext() { m_context = nullptr; }
 
   // OffscreenCanvasFrameDispatcherClient implementation
   void beginFrame() final;
 
   // EventTarget implementation
   const AtomicString& interfaceName() const final {
     return EventTargetNames::OffscreenCanvas;
   }
@@ skipping 46 matching lines @@
 
   IntSize m_size;
   bool m_isNeutered = false;
 
   bool m_originClean = true;
   bool m_disableReadingFromCanvas = false;
 
   bool isPaintable() const;
 
   std::unique_ptr<OffscreenCanvasFrameDispatcher> m_frameDispatcher;
+
   Member<ScriptPromiseResolver> m_commitPromiseResolver;
+  RefPtr<StaticBitmapImage> m_currentFrame;

[Justin Novosad, 2017/03/24 17:41:53]

Could we call this m_frameToDispatchAtEndOfTask

[xlai (Olivia), 2017/03/24 18:18:52]

I don't think this name is suitable. With the latest change,
m_currentFrame can be dispatched in two different situations:
1. at the end of task, in normal situation
2. onBeginFrame, when this particular frame is an overdraw frame that user
commit
when the previous m_currentFrame has been dispatched but
the promise is not resolved yet.

+  bool m_currentFrameIsWebGLSoftwareRendering = false;
   RefPtr<StaticBitmapImage> m_overdrawFrame;
   bool m_overdrawFrameIsWebGLSoftwareRendering = false;
+
   // cc::FrameSinkId is broken into two integer components as this can be used
   // in transfer of OffscreenCanvas across threads
   // If this object is not created via
   // HTMLCanvasElement.transferControlToOffscreen(),
   // then the following members would remain as initialized zero values.
   uint32_t m_clientId = 0;
   uint32_t m_sinkId = 0;
 };
 
 }  // namespace blink
 
 #endif  // OffscreenCanvas_h