services/ui: Allow injecting the IO thread task runner for gpu channel.

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 77 matching lines @@
 
 void WindowManagerApplication::InitWindowManager(
     ui::WindowTreeClient* window_tree_client) {
   InitializeComponents();
 
   window_manager_->Init(window_tree_client);
 }
 
 void WindowManagerApplication::OnStart(const shell::Identity& identity) {
   aura_init_.reset(new views::AuraInit(connector(), "ash_mus_resources.pak"));
-  gpu_service_ = ui::GpuService::Initialize(connector());
+  gpu_service_ = ui::GpuService::Create(connector());
   compositor_context_factory_.reset(
       new views::SurfaceContextFactory(gpu_service_.get()));
   aura::Env::GetInstance()->set_context_factory(
       compositor_context_factory_.get());
   window_manager_.reset(new WindowManager(connector()));
 
   MaterialDesignController::Initialize();
 
   tracing_.Initialize(connector(), identity.name());
 
@@ skipping 33 matching lines @@
       base::Bind(&WindowManagerApplication::OnAcceleratorRegistrarDestroyed,
                  base::Unretained(this))));
 }
 
 void WindowManagerApplication::ScreenlockStateChanged(bool locked) {
   window_manager_->SetScreenLocked(locked);
 }
 
 }  // namespace mus
 }  // namespace ash