gpu: Cleanup class/struct forward declarations

gpu/command_buffer/service/gles2_cmd_decoder_mock.h

 // Copyright (c) 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.
 
 // This file contains the mock GLES2Decoder class.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_MOCK_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_MOCK_H_
 
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 #include "gpu/command_buffer/service/shader_translator.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace gl {
 class GLContext;
 class GLSurface;
 }
 
 namespace gpu {
-class AsyncPixelTransferDelegate;
 
 namespace gles2 {
 
 class ContextGroup;
 class ErrorState;
 class QueryManager;
 struct ContextState;
 
 class MockGLES2Decoder : public GLES2Decoder {
  public:
@@ skipping 126 matching lines @@
   MOCK_CONST_METHOD0(WasContextLostByRobustnessExtension, bool());
   MOCK_METHOD1(MarkContextLost, void(gpu::error::ContextLostReason reason));
 
   DISALLOW_COPY_AND_ASSIGN(MockGLES2Decoder);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_MOCK_H_