Add decode() functionality to image elements.

cc/trees/single_thread_proxy.h

 // Copyright 2011 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 CC_TREES_SINGLE_THREAD_PROXY_H_
 #define CC_TREES_SINGLE_THREAD_PROXY_H_
 
 #include <limits>
 
 #include "base/cancelable_callback.h"
@@ skipping 82 matching lines @@
   bool IsInsideDraw() override;
   void RenewTreePriority() override {}
   void PostDelayedAnimationTaskOnImplThread(const base::Closure& task,
                                             base::TimeDelta delay) override {}
   void DidActivateSyncTree() override;
   void WillPrepareTiles() override;
   void DidPrepareTiles() override;
   void DidCompletePageScaleAnimationOnImplThread() override;
   void OnDrawForCompositorFrameSink(bool resourceless_software_draw) override;
   void NeedsImplSideInvalidation() override;
+  void NotifyImageDecodeRequestFinished() override;
 
   void RequestNewCompositorFrameSink();
 
   // Called by the legacy path where RenderWidget does the scheduling.
   void CompositeImmediately(base::TimeTicks frame_begin_time);
 
  protected:
   SingleThreadProxy(LayerTreeHost* layer_tree_host,
                     LayerTreeHostSingleThreadClient* client,
                     TaskRunnerProvider* task_runner_provider);
 
  private:
   void BeginMainFrame(const BeginFrameArgs& begin_frame_args);
   void BeginMainFrameAbortedOnImplThread(CommitEarlyOutReason reason);
   void DoBeginMainFrame(const BeginFrameArgs& begin_frame_args);
   void DoPainting();
   void DoCommit();
   DrawResult DoComposite(LayerTreeHostImpl::FrameData* frame);
   void DoSwap();
   void DidCommitAndDrawFrame();
   void CommitComplete();
 
   bool ShouldComposite() const;
   void ScheduleRequestNewCompositorFrameSink();
+  void IssueImageDecodeFinishedCallbacks();
 
   void DidReceiveCompositorFrameAck();
 
   // Accessed on main thread only.
   LayerTreeHost* layer_tree_host_;
   LayerTreeHostSingleThreadClient* single_thread_client_;
 
   TaskRunnerProvider* task_runner_provider_;
 
   // Used on the Thread, but checked on main thread during
@@ skipping 108 matching lines @@
  private:
   DebugScopedSetImplThread impl_thread_;
   DebugScopedSetMainThreadBlocked main_thread_blocked_;
 
   DISALLOW_COPY_AND_ASSIGN(DebugScopedSetImplThreadAndMainThreadBlocked);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_SINGLE_THREAD_PROXY_H_