Move DisplayManager and DisplayChangeObserverX11 from aura to ash.

ui/gfx/screen_win.h

 // 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.
 
 #ifndef UI_GFX_SCREEN_WIN_H_
 #define UI_GFX_SCREEN_WIN_H_
 
 #include "base/compiler_specific.h"
 #include "ui/base/ui_export.h"
 #include "ui/gfx/screen.h"
@@ skipping 11 matching lines @@
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
   virtual int GetNumDisplays() OVERRIDE;
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView window) const OVERRIDE;
   virtual gfx::Display GetDisplayNearestPoint(
       const gfx::Point& point) const OVERRIDE;
   virtual gfx::Display GetDisplayMatching(
       const gfx::Rect& match_rect) const OVERRIDE;
   virtual gfx::Display GetPrimaryDisplay() const OVERRIDE;
+  virtual void AddObserver(DisplayObserver* observer) OVERRIDE;
+  virtual void RemoveObserver(DisplayObserver* observer) OVERRIDE;
 
   // Returns the HWND associated with the NativeView.
   virtual HWND GetHWNDFromNativeView(NativeView window) const;
 
   // Returns the NativeView associated with the HWND.
   virtual NativeWindow GetNativeWindowFromHWND(HWND hwnd) const;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScreenWin);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_SCREEN_WIN_H_