Re-land: cc: Implement shared worker contexts.

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 20 matching lines @@
       LayerTreeHost* layer_tree_host,
       LayerTreeHostSingleThreadClient* client,
       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
       scoped_ptr<BeginFrameSource> external_begin_frame_source);
   ~SingleThreadProxy() override;
 
   // Proxy implementation
   void FinishAllRendering() override;
   bool IsStarted() const override;
   bool CommitToActiveTree() const override;
-  void SetOutputSurface(scoped_ptr<OutputSurface>) override;
-  scoped_ptr<OutputSurface> ReleaseOutputSurface() override;
+  void SetOutputSurface(OutputSurface* output_surface) override;
+  void ReleaseOutputSurface() override;
   void SetLayerTreeHostClientReady() override;
   void SetVisible(bool visible) override;
   void SetThrottleFrameProduction(bool throttle) override;
   const RendererCapabilities& GetRendererCapabilities() const override;
   void SetNeedsAnimate() override;
   void SetNeedsUpdateLayers() override;
   void SetNeedsCommit() override;
   void SetNeedsRedraw(const gfx::Rect& damage_rect) override;
   void SetNextCommitWaitsForActivation() override;
   void NotifyInputThrottledUntilCommit() override {}
@@ skipping 177 matching lines @@
  private:
   DebugScopedSetImplThread impl_thread_;
   DebugScopedSetMainThreadBlocked main_thread_blocked_;
 
   DISALLOW_COPY_AND_ASSIGN(DebugScopedSetImplThreadAndMainThreadBlocked);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_SINGLE_THREAD_PROXY_H_