Use persistent ID/names for displays.

ui/aura/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 UI_AURA_DISPLAY_MANAGER_H_
 #define UI_AURA_DISPLAY_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 66 matching lines @@
       const Window* window) const = 0;
 
   // Returns the display object nearest given |point|.
   virtual const gfx::Display& GetDisplayNearestPoint(
       const gfx::Point& point) const = 0;
 
   // Returns the display that most closely intersects |match_rect|.
   virtual const gfx::Display& GetDisplayMatching(
       const gfx::Rect& match_rect) const = 0;
 
+  // Returns the human-readable name for the display specified by |index|.
+  virtual std::string GetDisplayNameAt(size_t index) = 0;
+
  protected:
   // Calls observers' OnDisplayBoundsChanged methods.
   void NotifyBoundsChanged(const gfx::Display& display);
   void NotifyDisplayAdded(const gfx::Display& display);
   void NotifyDisplayRemoved(const gfx::Display& display);
 
  private:
   // If set before the RootWindow is created, the host window will cover the
   // entire display.  Note that this can still be overridden via the
   // switches::kAuraHostWindowSize flag.
   static bool use_fullscreen_host_window_;
 
   ObserverList<DisplayObserver> observers_;
   DISALLOW_COPY_AND_ASSIGN(DisplayManager);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_DISPLAY_MANAGER_H_