gpu: Directly cast ClientBuffer to gfx::GpuMemoryBuffer

gpu/ipc/client/gpu_memory_buffer_impl.cc

 // Copyright 2013 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.
 
 #include "gpu/ipc/client/gpu_memory_buffer_impl.h"
 
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.h"
 
@@ skipping 42 matching lines @@
     case gfx::OZONE_NATIVE_PIXMAP:
       return GpuMemoryBufferImplOzoneNativePixmap::CreateFromHandle(
           handle, size, format, usage, callback);
 #endif
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
-// static
-GpuMemoryBufferImpl* GpuMemoryBufferImpl::FromClientBuffer(
-    ClientBuffer buffer) {
-  return reinterpret_cast<GpuMemoryBufferImpl*>(buffer);
-}
-
 gfx::Size GpuMemoryBufferImpl::GetSize() const {
   return size_;
 }
 
 gfx::BufferFormat GpuMemoryBufferImpl::GetFormat() const {
   return format_;
 }
 
 gfx::GpuMemoryBufferId GpuMemoryBufferImpl::GetId() const {
   return id_;
 }
 
 ClientBuffer GpuMemoryBufferImpl::AsClientBuffer() {
   return reinterpret_cast<ClientBuffer>(this);
 }
 
 }  // namespace gpu