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

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 387 matching lines @@
   }
 
   // TODO(ekaramad): The reference to the focused pepper plugin will be removed
   // from RenderWidget. The purpose of having the reference here was to make IME
   // work for OOPIF (https://crbug.com/643727).
   void set_focused_pepper_plugin(PepperPluginInstanceImpl* plugin) {
     focused_pepper_plugin_ = plugin;
   }
 
   // When emulated, this returns original device scale factor.
-  float GetOriginalDeviceScaleFactor() const;
+  float GetOriginalDeviceScaleFactor() const override;
 
   // Helper to convert |point| using ConvertWindowToViewport().
   gfx::Point ConvertWindowPointToViewport(const gfx::Point& point);
 
  protected:
   // Friend RefCounted so that the dtor can be non-public. Using this class
   // without ref-counting is an error.
   friend class base::RefCounted<RenderWidget>;
 
   // For unit tests.
@@ skipping 414 matching lines @@
   // being handled. If the current event results in starting a drag/drop
   // session, this info is sent to the browser along with other drag/drop info.
   DragEventSourceInfo possible_drag_event_info_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_