Allow switching between extended and unified

ash/display/display_manager.h

Index: ash/display/display_manager.h
diff --git a/ash/display/display_manager.h b/ash/display/display_manager.h
index b6ac0926c04b02aadc48480b33c033d31bac00d6..8c6dd0dd1cfd488172153bcef8acba904d8ff750 100644
--- a/ash/display/display_manager.h
+++ b/ash/display/display_manager.h
@@ -297,6 +297,11 @@ class ASH_EXPORT DisplayManager
     return default_multi_display_mode_;
   }
 
+  // Reconfigure display configuration using the same
+  // physical display. TODO(oshima): Refactor and move this
+  // impl to |SetDefaultMultiDisplayMode|.
+  void ReconfigureDisplays();

[oshima, 2015/05/19 23:55:15]

I tried to keep the CL minimum to make merge easier. I'll refactor and simplify
the code once the feature is settled on 44.

+
   // Update the bounds of the display given by |display_id|.
   bool UpdateDisplayBounds(int64 display_id,
                            const gfx::Rect& new_bounds);