Re-home the global MessageCenter to support Ash+Win environments.

ash/shell.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 "ash/shell.h"
 
 #include <algorithm>
 #include <string>
 
 #include "ash/accelerators/focus_manager_factory.h"
@@ skipping 840 matching lines @@
   root->ShowRootWindow();
   // Activate new root for testing.
   active_root_window_ = root;
 }
 
 void Shell::DoInitialWorkspaceAnimation() {
   return GetPrimaryRootWindowController()->workspace_controller()->
       DoInitialAnimation();
 }
 
-message_center::MessageCenter* Shell::message_center() {
-  if (!message_center_.get())
-    message_center_.reset(new message_center::MessageCenter());
-  return message_center_.get();
-}
-
 void Shell::InitRootWindowController(
     internal::RootWindowController* controller) {
   aura::RootWindow* root_window = controller->root_window();
   DCHECK(activation_client_);
   DCHECK(visibility_controller_.get());
   DCHECK(drag_drop_controller_.get());
   DCHECK(capture_controller_.get());
   DCHECK(window_cycle_controller_.get());
 
   aura::client::SetFocusClient(root_window, focus_client_.get());
@@ skipping 71 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // Shell, aura::client::ActivationChangeObserver implementation:
 
 void Shell::OnWindowActivated(aura::Window* gained_active,
                               aura::Window* lost_active) {
   if (gained_active)
     active_root_window_ = gained_active->GetRootWindow();
 }
 
 }  // namespace ash