Chrome OS: Ash support for >=3 displays.

ash/display/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_DISPLAY_MANAGER_H_
 #define ASH_DISPLAY_DISPLAY_MANAGER_H_
 
 #include <string>
 #include <vector>
 
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   // you must use |GetDisplayInfo| to get the correct DisplayInfo for
   // a display.
   void InsertAndUpdateDisplayInfo(const DisplayInfo& new_info);
 
   // Called when the display info is updated through InsertAndUpdateDisplayInfo.
   void OnDisplayInfoUpdated(const DisplayInfo& display_info);
 
   // Creates a display object from the DisplayInfo for |display_id|.
   gfx::Display CreateDisplayFromDisplayInfoById(int64 display_id);
 
-  // Updates the bounds of the secondary display in |display_list|
-  // using the layout registered for the display pair and set the
-  // index of display updated to |updated_index|. Returns true
-  // if the secondary display's bounds has been changed from current
-  // value, or false otherwise.
-  bool UpdateSecondaryDisplayBoundsForLayout(DisplayList* display_list,
-                                             size_t* updated_index) const;
+  // Updates the bounds of all non-primary displays in |display_list| and
+  // append the indices of displays updated to |updated_indices|.
+  // When the size of |display_list| equals 2, the bounds are updated using
+  // the layout registered for the display pair. For more than 2 displays,
+  // the bounds are updated using horizontal layout.
+  // Returns true if any of the non-primary display's bounds has been changed
+  // from current value, or false otherwise.
+  bool UpdateNonPrimaryDisplayBoundsForLayout(
+      DisplayList* display_list, std::vector<size_t>* updated_indices) const;
 
   void CreateMirrorWindowIfAny();
 
   bool HasSoftwareMirroringDisplay();
 
   static void UpdateDisplayBoundsForLayout(
       const DisplayLayout& layout,
       const gfx::Display& primary_display,
       gfx::Display* secondary_display);
 
@@ skipping 38 matching lines @@
   gfx::Display::Rotation registered_internal_display_rotation_;
 
   base::WeakPtrFactory<DisplayManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_DISPLAY_MANAGER_H_