Add OnDisplayMetricsChanged in DisplayObserver.

ash/wm/maximize_mode/maximize_mode_window_manager.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 ASH_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_WINDOW_MANAGER_H_
 #define ASH_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_WINDOW_MANAGER_H_
 
 #include <map>
 #include <set>
 
@@ skipping 38 matching lines @@
   virtual void OnOverviewModeStarting() OVERRIDE;
   virtual void OnOverviewModeEnding() OVERRIDE;
 
   // Overridden from WindowObserver:
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
   virtual void OnWindowAdded(aura::Window* window) OVERRIDE;
   virtual void OnWindowBoundsChanged(aura::Window* window,
                                      const gfx::Rect& old_bounds,
                                      const gfx::Rect& new_bounds) OVERRIDE;
 
-  // aura::DisplayObserver overrides:
-  virtual void OnDisplayBoundsChanged(
-      const gfx::Display& display) OVERRIDE;
+  // gfx::DisplayObserver overrides:
   virtual void OnDisplayAdded(const gfx::Display& display) OVERRIDE;
   virtual void OnDisplayRemoved(const gfx::Display& display) OVERRIDE;
+  virtual void OnDisplayMetricsChanged(const gfx::Display& display,
+                                       uint32_t metrics) OVERRIDE;
 
   // ui::EventHandler override:
   virtual void OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
 
  protected:
   friend class ash::Shell;
 
   // The object should only be created by the ash::Shell.
   MaximizeModeWindowManager();
 
@@ skipping 43 matching lines @@
 
   // True if all backdrops are hidden.
   bool backdrops_hidden_;
 
   DISALLOW_COPY_AND_ASSIGN(MaximizeModeWindowManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_WINDOW_MANAGER_H_