A couple of multiple displays support fixes.

ui/gfx/display.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_GFX_DISPLAY_H_
 #define UI_GFX_DISPLAY_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/base/ui_export.h"
@@ skipping 11 matching lines @@
   // "--force-device-scale-factor".
   static float GetForcedDeviceScaleFactor();
 
   // Creates a display with invalid id(-1) as default.
   Display();
   explicit Display(int id);
   Display(int id, const Rect& bounds);
   ~Display();
 
   // Sets/Gets unique identifier associated with the display.
+  // -1 means invalid display and it doesn't not exit.
   int id() const { return id_; }
   void set_id(int id) { id_ = id; }
 
   // Gets/Sets the display's bounds in gfx::Screen's coordinates.
-  // -1 means invalid display and it doesn't not exit.
   const Rect& bounds() const { return bounds_; }
   void set_bounds(const Rect& bounds) { bounds_ = bounds; }
 
   // Gets/Sets the display's work area in gfx::Screen's coordinates.
   const Rect& work_area() const { return work_area_; }
   void set_work_area(const Rect& work_area) { work_area_ = work_area; }
 
   // Output device's pixel scale factor. This specifies how much the
   // UI should be scaled when the actual output has more pixels than
   // standard displays (which is around 100~120dpi.) The potential return
@@ skipping 42 matching lines @@
   Rect work_area_;
 #if defined(USE_AURA)
   Rect bounds_in_pixel_;
 #endif
   float device_scale_factor_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_DISPLAY_H_