Introduce gpu_fuzzer to fuzz the GPU command buffers

gpu/command_buffer/service/command_buffer_service.h

Index: gpu/command_buffer/service/command_buffer_service.h
diff --git a/gpu/command_buffer/service/command_buffer_service.h b/gpu/command_buffer/service/command_buffer_service.h
index c3e4b17a4111d4fc41b11bf41600f70ff91c4d77..0d305bf2582e29740f3b72ccb2a2c7331bc65986 100644
--- a/gpu/command_buffer/service/command_buffer_service.h
+++ b/gpu/command_buffer/service/command_buffer_service.h
@@ -95,6 +95,7 @@ class GPU_EXPORT CommandBufferService : public CommandBufferServiceBase {
   // to identify it in the command buffer.
   bool RegisterTransferBuffer(int32_t id,
                               std::unique_ptr<BufferBacking> buffer);
+  scoped_refptr<Buffer> CreateTransferBufferWithId(size_t size, int32_t id);
 
  private:
   int32_t ring_buffer_id_;