Use persistent ID/names for displays.

ash/display/display_controller.h

Index: ash/display/display_controller.h
diff --git a/ash/display/display_controller.h b/ash/display/display_controller.h
index f625ee55890c28979a57f901a4bc346485688cd7..fa41ab065628ee8e3181e12ba4a01b8095f59086 100644
--- a/ash/display/display_controller.h
+++ b/ash/display/display_controller.h
@@ -92,11 +92,12 @@ class ASH_EXPORT DisplayController : public aura::DisplayObserver {
  private:
   // Creates a root window for |display| and stores it in the |root_windows_|
   // map.

[oshima, 2012/08/10 03:09:51]

// TODO(oshima): remove |is_primary| when non extended desktop mode is removed.

[Jun Mukai, 2012/08/10 09:39:52]

Done.

-  aura::RootWindow* AddRootWindowForDisplay(const gfx::Display& display);
+  aura::RootWindow* AddRootWindowForDisplay(const gfx::Display& display,
+                                            bool is_primary);
 
   void UpdateDisplayBoundsForLayout();
 
-  std::map<int, aura::RootWindow*> root_windows_;
+  std::map<int64, aura::RootWindow*> root_windows_;
 
   SecondaryDisplayLayout secondary_display_layout_;