gpu: Directly cast ClientBuffer to gfx::GpuMemoryBuffer

gpu/command_buffer/client/gpu_memory_buffer_manager.h

Index: gpu/command_buffer/client/gpu_memory_buffer_manager.h
diff --git a/gpu/command_buffer/client/gpu_memory_buffer_manager.h b/gpu/command_buffer/client/gpu_memory_buffer_manager.h
index 1f56123d03afa51e2752e163cd38470ef4bd7d0f..921b42e8e34ff6fa2dde9e4593e80e6ff133e5bc 100644
--- a/gpu/command_buffer/client/gpu_memory_buffer_manager.h
+++ b/gpu/command_buffer/client/gpu_memory_buffer_manager.h
@@ -33,11 +33,6 @@ class GPU_EXPORT GpuMemoryBufferManager {
       const gfx::Size& size,
       gfx::BufferFormat format) = 0;
 
-  // Returns a GpuMemoryBuffer instance given a ClientBuffer. Returns NULL on
-  // failure.
-  virtual gfx::GpuMemoryBuffer* GpuMemoryBufferFromClientBuffer(
-      ClientBuffer buffer) = 0;
-
   // Associates destruction sync point with |buffer|.
   virtual void SetDestructionSyncToken(gfx::GpuMemoryBuffer* buffer,
                                        const gpu::SyncToken& sync_token) = 0;