[DevTools] Use device metrics emulation implemented in content.

Source/web/WebInputEventConversion.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 45 matching lines @@
 
 static float widgetScaleFactor(const Widget* widget)
 {
     if (!widget)
         return 1;
 
     ScrollView* rootView = widget->root();
     if (!rootView)
         return 1;
 
-    return rootView->visibleContentScaleFactor();
+    return rootView->inputEventsScaleFactor();
 }
 
 // MakePlatformMouseEvent -----------------------------------------------------
 
 PlatformMouseEventBuilder::PlatformMouseEventBuilder(Widget* widget, const WebMouseEvent& e)
 {
     float scale = widgetScaleFactor(widget);
     // FIXME: Widget is always toplevel, unless it's a popup. We may be able
     // to get rid of this once we abstract popups into a WebKit API.
     m_position = widget->convertFromContainingWindow(IntPoint(e.x / scale, e.y / scale));
@@ skipping 661 matching lines @@
     modifiers = getWebInputModifiers(event);
 
     globalX = event.screenX();
     globalY = event.screenY();
     IntPoint localPoint = convertAbsoluteLocationForRenderObject(event.absoluteLocation(), *renderObject);
     x = localPoint.x();
     y = localPoint.y();
 }
 
 } // namespace WebKit