Use persistent ID/names for displays.

ash/display/multi_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_MULTI_DISPLAY_MANAGER_H_
 #define ASH_DISPLAY_MULTI_DISPLAY_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 41 matching lines @@
       const gfx::Display& display) OVERRIDE;
   virtual gfx::Display* GetDisplayAt(size_t index) OVERRIDE;
 
   virtual size_t GetNumDisplays() const OVERRIDE;
   virtual const gfx::Display& GetDisplayNearestPoint(
       const gfx::Point& point) const OVERRIDE;
   virtual const gfx::Display& GetDisplayNearestWindow(
       const aura::Window* window) const OVERRIDE;
   virtual const gfx::Display& GetDisplayMatching(
       const gfx::Rect& match_rect)const OVERRIDE;
+  virtual std::string GetDisplayNameAt(size_t index) OVERRIDE;
 
   // RootWindowObserver overrides:
   virtual void OnRootWindowResized(const aura::RootWindow* root,
                                    const gfx::Size& new_size) OVERRIDE;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ExtendedDesktopTest, ConvertPoint);
   typedef std::vector<gfx::Display> Displays;
 
   void Init();
   void AddRemoveDisplayImpl();
   void CycleDisplayImpl();
   void ScaleDisplayImpl();
   gfx::Display& FindDisplayForRootWindow(const aura::RootWindow* root);
 
   // Refer to |aura::DisplayManager::CreateDisplayFromSpec| API for
   // the format of |spec|.
   void AddDisplayFromSpec(const std::string& spec);
 
   Displays displays_;
 
   DISALLOW_COPY_AND_ASSIGN(MultiDisplayManager);
 };
 
-extern const aura::WindowProperty<int>* const kDisplayIdKey;
+extern const aura::WindowProperty<int64>* const kDisplayIdKey;
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_MULTI_DISPLAY_MANAGER_H_