[DevTools] Handle emulated device scale factor and original device scale factor properly.

content/renderer/render_widget.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 CONTENT_RENDERER_RENDER_WIDGET_H_
 #define CONTENT_RENDERER_RENDER_WIDGET_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 748 matching lines @@
   // are sent to each frame in the list for events such as changing
   // visibility state for example.
   base::ObserverList<RenderFrameImpl> render_frames_;
 
   bool has_host_context_menu_location_;
   gfx::Point host_context_menu_location_;
 
   scoped_ptr<scheduler::RenderWidgetSchedulingState>
       render_widget_scheduling_state_;
 
+ private:
+  // When emulated, this returns original device scale factor.
+  float GetOriginalDeviceScaleFactor() const;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_