Use mus::MojoGpuMemoryBufferManager in mus::GpuService.

components/mus/common/mojo_buffer_backing.cc

 // Copyright 2014 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 "components/mus/gles2/mojo_buffer_backing.h"
+#include "components/mus/common/mojo_buffer_backing.h"
 
 #include "base/logging.h"
 
 namespace mus {
 
 MojoBufferBacking::MojoBufferBacking(mojo::ScopedSharedBufferHandle handle,
                                      void* memory,
                                      size_t size)
     : handle_(std::move(handle)), memory_(memory), size_(size) {}
 
@@ skipping 15 matching lines @@
       new MojoBufferBacking(std::move(handle), memory, size));
 }
 void* MojoBufferBacking::GetMemory() const {
   return memory_;
 }
 size_t MojoBufferBacking::GetSize() const {
   return size_;
 }
 
 }  // namespace mus