Rework FlushSync to return early if commands have been processed since the last update

gpu/command_buffer/service/gpu_scheduler_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_SERVICE_GPU_SCHEDULER_MOCK_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_MOCK_H_
 
 #include "gpu/command_buffer/service/gpu_scheduler.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace gpu {
 
 class MockGpuScheduler : public GpuScheduler {
  public:
   explicit MockGpuScheduler(CommandBuffer* command_buffer)
       : GpuScheduler(command_buffer) {
   }
 
-  MOCK_METHOD0(ProcessCommands, void());
   MOCK_METHOD1(GetSharedMemoryBuffer, Buffer(int32 shm_id));
   MOCK_METHOD1(set_token, void(int32 token));
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockGpuScheduler);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_MOCK_H_