Populates sourceDevice attribute into MouseEvent

Source/core/events/UIEvent.h

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 40 matching lines @@
     {
         return adoptRefWillBeNoop(new UIEvent(type, initializer));
     }
     virtual ~UIEvent();
 
     void initUIEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtrWillBeRawPtr<AbstractView>, int detail);
 
     AbstractView* view() const { return m_view.get(); }
     int detail() const { return m_detail; }
     InputDevice* sourceDevice() const { return m_sourceDevice.get(); }
+    void setSourceDevice(InputDevice* sourceDevice) { m_sourceDevice = sourceDevice; }
 
     virtual const AtomicString& interfaceName() const override;
     virtual bool isUIEvent() const override final;
 
     virtual int keyCode() const;
     virtual int charCode() const;
 
     virtual int layerX();
     virtual int layerY();
 
@@ skipping 11 matching lines @@
 
 private:
     RefPtrWillBeMember<AbstractView> m_view;
     int m_detail;
     PersistentWillBeMember<InputDevice> m_sourceDevice;
 };
 
 } // namespace blink
 
 #endif // UIEvent_h