Remove old texture path in TextureLayer

cc/layers/texture_layer_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_LAYERS_TEXTURE_LAYER_CLIENT_H_
 #define CC_LAYERS_TEXTURE_LAYER_CLIENT_H_
 
 #include "cc/resources/single_release_callback.h"
 
 namespace cc {
 class ResourceUpdateQueue;
 class TextureMailbox;
 
 class TextureLayerClient {
  public:
-  // Called to prepare this layer's texture for compositing.
-  // Returns the texture ID to be used for compositing.
-  virtual unsigned PrepareTexture() = 0;
-
   // Returns true and provides a mailbox if a new frame is available.
   // Returns false if no new data is available
   // and the old mailbox is to be reused.
   virtual bool PrepareTextureMailbox(
       TextureMailbox* mailbox,
       scoped_ptr<SingleReleaseCallback>* release_callback,
       bool use_shared_memory) = 0;
 
  protected:
   virtual ~TextureLayerClient() {}
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_TEXTURE_LAYER_CLIENT_H_