Fix mouse wheel over-scrolls when display is scaled and scroll is paginated

third_party/WebKit/public/web/WebWidgetClient.h

 /*
  * 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 169 matching lines @@
   // migration is completed.
   virtual void convertWindowToViewport(WebFloatRect* rect) {}
 
   // Called when a drag-and-drop operation should begin.
   virtual void startDragging(WebReferrerPolicy,
                              const WebDragData&,
                              WebDragOperationsMask,
                              const WebImage& dragImage,
                              const WebPoint& dragImageOffset) {}
 
+  // This returns original device scale factor.
+  virtual float GetOriginalDeviceScaleFactor() const { return 1.0f; }
+
  protected:
   ~WebWidgetClient() {}
 };
 
 }  // namespace blink
 
 #endif