Introduce separate client and init path for single-threaded cc

cc/trees/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_TREES_LAYER_TREE_HOST_CLIENT_H_
 #define CC_TREES_LAYER_TREE_HOST_CLIENT_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 
@@ skipping 18 matching lines @@
                                    float page_scale) = 0;
   // Creates an OutputSurface. If fallback is true, it should attempt to
   // create an OutputSurface that is guaranteed to initialize correctly.
   virtual scoped_ptr<OutputSurface> CreateOutputSurface(bool fallback) = 0;
   virtual void DidInitializeOutputSurface(bool success) = 0;
   virtual void WillCommit() = 0;
   virtual void DidCommit() = 0;
   virtual void DidCommitAndDrawFrame() = 0;
   virtual void DidCompleteSwapBuffers() = 0;
 
-  // Used only in the single-threaded path.
-  virtual void ScheduleComposite() = 0;
-
   // If the client provides an OutputSurface bound to a 3d context for direct
   // rendering, this must return a provider that provides contexts usable from
   // the same thread as the OutputSurface's context.
   virtual scoped_refptr<cc::ContextProvider> OffscreenContextProvider() = 0;
 
   // Requests that the client insert a rate limiting token in the shared main
   // thread context's command stream that will block if the context gets too far
   // ahead of the compositor's command stream. Only needed if the tree contains
   // a TextureLayer that calls SetRateLimitContext(true).
   virtual void RateLimitSharedMainThreadContext() {}
 
   // This hook is for testing.
   virtual void DidFailToInitializeOutputSurface() {}
 
  protected:
   virtual ~LayerTreeHostClient() {}
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_CLIENT_H_