Introduce separate client and init path for single-threaded cc

cc/test/fake_layer_tree_host_client.h

 // Copyright 2012 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_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_
 #define CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/input/input_handler.h"
 #include "cc/test/test_context_provider.h"
-#include "cc/trees/layer_tree_host.h"
+#include "cc/trees/layer_tree_host_client.h"
+#include "cc/trees/layer_tree_host_single_thread_client.h"
 
 namespace cc {
 class OutputSurface;
 
-class FakeLayerTreeHostClient : public LayerTreeHostClient {
+class FakeLayerTreeHostClient : public LayerTreeHostClient,
+                                public LayerTreeHostSingleThreadClient {
  public:
   enum RendererOptions {
     DIRECT_3D,
     DIRECT_SOFTWARE,
     DELEGATED_3D,
     DELEGATED_SOFTWARE
   };
   explicit FakeLayerTreeHostClient(RendererOptions options);
   virtual ~FakeLayerTreeHostClient();
 
+  // LayerTreeHostClient implementation.
   virtual void WillBeginMainFrame() OVERRIDE {}
   virtual void DidBeginMainFrame() OVERRIDE {}
   virtual void Animate(double frame_begin_time) OVERRIDE {}
   virtual void Layout() OVERRIDE {}
   virtual void ApplyScrollAndScale(gfx::Vector2d scroll_delta,
                                    float page_scale) OVERRIDE {}
 
   virtual scoped_ptr<OutputSurface> CreateOutputSurface(bool fallback) OVERRIDE;
   virtual void DidInitializeOutputSurface(bool success) OVERRIDE {}
   virtual void WillCommit() OVERRIDE {}
   virtual void DidCommit() OVERRIDE {}
   virtual void DidCommitAndDrawFrame() OVERRIDE {}
   virtual void DidCompleteSwapBuffers() OVERRIDE {}
+  virtual scoped_refptr<ContextProvider> OffscreenContextProvider() OVERRIDE;
 
-  // Used only in the single-threaded path.
+  // LayerTreeHostSingleThreadClient implementation.
   virtual void ScheduleComposite() OVERRIDE {}
-
-  virtual scoped_refptr<ContextProvider> OffscreenContextProvider() OVERRIDE;
+  virtual void DidPostSwapBuffers() OVERRIDE {}
+  virtual void DidAbortSwapBuffers() OVERRIDE {}
 
  private:
   bool use_software_rendering_;
   bool use_delegating_renderer_;
 
   scoped_refptr<TestContextProvider> offscreen_contexts_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_