services/ui: Have an explicit lifetime/ownership of ui::GpuService.

ash/mus/window_manager_application.cc

 // Copyright 2015 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 "ash/mus/window_manager_application.h"
 
 #include <utility>
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/mus/accelerators/accelerator_registrar_impl.h"
@@ skipping 60 matching lines @@
   // AcceleratorRegistrarImpl removes an observer in its destructor. Destroy
   // it early on.
   std::set<AcceleratorRegistrarImpl*> accelerator_registrars(
       accelerator_registrars_);
   for (AcceleratorRegistrarImpl* registrar : accelerator_registrars)
     registrar->Destroy();
 
   // Destroy the WindowManager while still valid. This way we ensure
   // OnWillDestroyRootWindowController() is called (if it hasn't been already).
   window_manager_.reset();
-
+  gpu_service_.reset();
   ShutdownComponents();
 }
 
 void WindowManagerApplication::OnAcceleratorRegistrarDestroyed(
     AcceleratorRegistrarImpl* registrar) {
   accelerator_registrars_.erase(registrar);
 }
 
 void WindowManagerApplication::InitWindowManager(
     ui::WindowTreeClient* window_tree_client) {
   InitializeComponents();
 
   window_manager_->Init(window_tree_client);
   window_manager_->AddObserver(this);
 }
 
 void WindowManagerApplication::OnStart(const shell::Identity& identity) {
-  ui::GpuService::Initialize(connector());
+  gpu_service_ = ui::GpuService::Initialize(connector());
   window_manager_.reset(new WindowManager(connector()));
 
   aura_init_.reset(new views::AuraInit(connector(), "ash_mus_resources.pak"));
   MaterialDesignController::Initialize();
 
   tracing_.Initialize(connector(), identity.name());
 
   ui::WindowTreeClient* window_tree_client = new ui::WindowTreeClient(
       window_manager_.get(), window_manager_.get(), nullptr);
   window_tree_client->ConnectAsWindowManager(connector());
@@ skipping 88 matching lines @@
     RootWindowController* controller) {
   // TODO(msw): this isn't right, ownership should belong in WindowManager
   // and/or RootWindowController. But this is temporary until we get rid of
   // sysui.
   shelf_layout_.reset();
   user_window_controller_.reset();
 }
 
 }  // namespace mus
 }  // namespace ash