Move DisplayManager and DisplayChangeObserverX11 from aura to ash.

ash/screen_ash.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 ASH_SCREEN_ASH_H_
 #define ASH_SCREEN_ASH_H_
 
 #include "ash/ash_export.h"
 #include "base/compiler_specific.h"
+#include "base/observer_list.h"
 #include "ui/gfx/screen.h"
 
 namespace gfx {
 class Rect;
 }
 
 namespace ash {
 
 // Aura implementation of gfx::Screen. Implemented here to avoid circular
 // dependencies.
@@ skipping 28 matching lines @@
                                          const gfx::Rect& rect);
 
   // Returns a gfx::Display object for secondary display. Returns
   // invalid display if there is no secondary display connected.
   static const gfx::Display& GetSecondaryDisplay();
 
   // Returns a gfx::Display object for the specified id.  Returns
   // invalid display if no such display is connected.
   static const gfx::Display& GetDisplayForId(int64 display_id);
 
+  // Notifies observers of display configuration changes.
+  void NotifyBoundsChanged(const gfx::Display& display);
+  void NotifyDisplayAdded(const gfx::Display& display);
+  void NotifyDisplayRemoved(const gfx::Display& display);
+
  protected:
   // Implementation of gfx::Screen:
   virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
-
   virtual int GetNumDisplays() OVERRIDE;
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView view) 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(gfx::DisplayObserver* observer) OVERRIDE;
+  virtual void RemoveObserver(gfx::DisplayObserver* observer) OVERRIDE;
 
  private:
+  ObserverList<gfx::DisplayObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(ScreenAsh);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SCREEN_ASH_H_