Add OnDisplayMetricsChanged in DisplayObserver.

ash/display/display_manager.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_DISPLAY_DISPLAY_MANAGER_H_
 #define ASH_DISPLAY_DISPLAY_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 87 matching lines @@
   DisplayLayoutStore* layout_store() {
     return layout_store_.get();
   }
 
   gfx::Screen* screen() {
     return screen_;
   }
 
   void set_delegate(Delegate* delegate) { delegate_ = delegate; }
 
-  // When set to true, the MonitorManager calls OnDisplayBoundsChanged
+  // When set to true, the MonitorManager calls OnDisplayMetricsChanged
   // even if the display's bounds didn't change. Used to swap primary
   // display.
   void set_force_bounds_changed(bool force_bounds_changed) {
     force_bounds_changed_ = force_bounds_changed;
   }
 
   // Returns the display id of the first display in the outupt list.
   int64 first_display_id() const { return first_display_id_; }
 
   // Initializes displays using command line flag. Returns false
@@ skipping 242 matching lines @@
   SecondDisplayMode second_display_mode_;
   int64 mirrored_display_id_;
   gfx::Display non_desktop_display_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_DISPLAY_MANAGER_H_