Revert of services/ui: Use new gpu::GpuInit to do the GPU initialization.

services/ui/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")
 import("//services/shell/public/service_manifest.gni")
 import("//testing/test.gni")
 
 source_set("gpu") {
   output_name = "mus_gpu"
 
   sources = [
-    "gpu_main.cc",
-    "gpu_main.h",
     "gpu_service_internal.cc",
     "gpu_service_internal.h",
   ]
 
   defines = [ "NOTIMPLEMENTED_POLICY=5" ]
 
   deps = [
     "//gpu/ipc/common",
     "//gpu/ipc/service",
     "//ipc",
@@ skipping 32 matching lines @@
 
   data_deps = [
     ":mus_gpu_unittests_app_manifest",
   ]
 }
 
 service_manifest("mus_gpu_unittests_app_manifest") {
   name = "mus_gpu_unittests_app"
   source = "mus_gpu_unittests_app_manifest.json"
 }