Use mus::MojoGpuMemoryBufferManager in mus::GpuService.

components/mus/gpu/BUILD.gn

 # Copyright 2016 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.
 
 import("//mojo/public/mojo_application_manifest.gni")
 import("//testing/test.gni")
 
 source_set("gpu") {
   output_name = "mus_gpu"
 
   sources = [
-    "gpu_memory_buffer_manager_mus_local.cc",
-    "gpu_memory_buffer_manager_mus_local.h",
     "gpu_service_impl.cc",
     "gpu_service_impl.h",
     "gpu_service_mus.cc",
     "gpu_service_mus.h",
   ]
 
   deps = [
     "//components/mus/common:mus_common",
     "//components/mus/public/interfaces",
     "//gpu/ipc/common",
@@ skipping 26 matching lines @@
 
   data_deps = [
     ":mus_gpu_unittests_app_manifest",
   ]
 }
 
 mojo_application_manifest("mus_gpu_unittests_app_manifest") {
   application_name = "mus_gpu_unittests_app"
   source = "mus_gpu_unittests_app_manifest.json"
 }