gpu: Cleanup class/struct forward declarations

gpu/command_buffer/common/command_buffer_mock.h

 // Copyright (c) 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 GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_MOCK_H_
 #define GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_MOCK_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "gpu/command_buffer/service/command_buffer_service.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
-namespace base {
-class SharedMemory;
-}
-
 namespace gpu {
 
 // An NPObject that implements a shared memory command buffer and a synchronous
 // API to manage the put and get pointers.
 class MockCommandBuffer : public CommandBufferServiceBase {
  public:
   MockCommandBuffer();
   virtual ~MockCommandBuffer();
 
   MOCK_METHOD0(GetLastState, State());
@@ skipping 15 matching lines @@
   MOCK_METHOD0(InsertSyncPoint, uint32_t());
   MOCK_METHOD0(GetPutOffset, int32_t());
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockCommandBuffer);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_MOCK_H_