mus: Rename GpuService to Gpu.

services/ui/public/cpp/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("//build/config/ui.gni")
 
 source_set("gpu") {
   sources = [
-    "gpu_service.h",
+    "gpu.h",
   ]
 
   deps = [
     ":internal",
     "//gpu/ipc/client",
     "//services/ui/public/interfaces",
   ]
 
   allow_circular_includes_from = [ ":internal" ]
 }
 
 source_set("internal") {
   visibility = [
     ":gpu",
     "//services/ui/demo:lib",
   ]
 
   sources = [
     "client_gpu_memory_buffer_manager.cc",
     "client_gpu_memory_buffer_manager.h",
-    "gpu_service.cc",
+    "gpu.cc",
   ]
 
   deps = [
     "//base",
     "//gpu/command_buffer/client",
     "//gpu/ipc/client",
     "//mojo/public/cpp/system",
     "//services/service_manager/public/cpp",
     "//services/ui/common:mus_common",
     "//services/ui/public/interfaces",
   ]
 }