Make ui::DisplayConfigurator a singleton

extensions/shell/browser/shell_desktop_controller_aura.h

 // Copyright 2014 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.
 
 #ifndef EXTENSIONS_SHELL_BROWSER_SHELL_DESKTOP_CONTROLLER_AURA_H_
 #define EXTENSIONS_SHELL_BROWSER_SHELL_DESKTOP_CONTROLLER_AURA_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 93 matching lines @@
   void CreateRootWindow();
 
   // Closes and destroys the root window hosting the app.
   void DestroyRootWindow();
 
   // Returns the dimensions (in pixels) of the primary display, or an empty size
   // if the dimensions can't be determined or no display is connected.
   gfx::Size GetPrimaryDisplaySize();
 
 #if defined(OS_CHROMEOS)
-  scoped_ptr<ui::DisplayConfigurator> display_configurator_;
+  ui::DisplayConfigurator* display_configurator_;
 #endif
 
   scoped_ptr<ShellScreen> screen_;
 
   scoped_ptr<aura::WindowTreeHost> host_;
 
   scoped_ptr<wm::CompoundEventFilter> root_window_event_filter_;
 
   scoped_ptr<aura::client::DefaultCaptureClient> capture_client_;
 
@@ skipping 12 matching lines @@
 
   // NativeAppWindow::Close() deletes the AppWindow.
   std::vector<AppWindow*> app_windows_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellDesktopControllerAura);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_SHELL_BROWSER_SHELL_DESKTOP_CONTROLLER_AURA_H_