2x Cursor support.

ui/aura/root_window_host.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_ROOT_WINDOW_HOST_H_
 #define UI_AURA_ROOT_WINDOW_HOST_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 81 matching lines @@
 
   // Grabs the snapshot of the root window by using the platform-dependent APIs.
   virtual bool GrabSnapshot(
       const gfx::Rect& snapshot_bounds,
       std::vector<unsigned char>* png_representation) = 0;
 
   // Posts |native_event| to the platform's event queue.
 #if !defined(OS_MACOSX)
   virtual void PostNativeEvent(const base::NativeEvent& native_event) = 0;
 #endif
+
+  // Called when the device scale factor of the root window has chagned.
+  virtual void OnDeviceScaleFactorChanged(float device_scale_factor) = 0;
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_ROOT_WINDOW_HOST_H_