CrOS: Enable threaded UI compositor by default.

ui/aura/env.cc

 // Copyright (c) 2012 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 "ui/aura/env.h"
 
 #include "base/command_line.h"
 #include "ui/aura/env_observer.h"
 #include "ui/aura/root_window_host.h"
 #include "ui/aura/window.h"
@@ skipping 73 matching lines @@
 void Env::Init() {
 #if !defined(USE_X11) && !defined(USE_MESSAGEPUMP_LINUX)
   dispatcher_.reset(CreateDispatcher());
 #endif
 #if defined(USE_X11)
   // We can't do this with a root window listener because XI_HierarchyChanged
   // messages don't have a target window.
   base::MessagePumpAuraX11::Current()->AddObserver(
       &device_list_updater_aurax11_);
 #endif
-  ui::Compositor::Initialize(
-      CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kUIEnableThreadedCompositing));
+  ui::Compositor::Initialize();
 }
 
 void Env::NotifyWindowInitialized(Window* window) {
   FOR_EACH_OBSERVER(EnvObserver, observers_, OnWindowInitialized(window));
 }
 
 void Env::NotifyRootWindowInitialized(RootWindow* root_window) {
   FOR_EACH_OBSERVER(EnvObserver,
                     observers_,
                     OnRootWindowInitialized(root_window));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // Env, ui::EventTarget implementation:
 
 bool Env::CanAcceptEvent(const ui::Event& event) {
   return true;
 }
 
 ui::EventTarget* Env::GetParentTarget() {
   return NULL;
 }
 
 }  // namespace aura