Populates sourceDevice attribute into TouchEvent

Source/core/events/UIEvent.cpp

 /*
  * 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, 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 14 matching lines @@
 
 
 namespace blink {
 
 UIEvent::UIEvent()
     : m_detail(0)
     , m_sourceDevice(nullptr)
 {
 }
 
-UIEvent::UIEvent(const AtomicString& eventType, bool canBubbleArg, bool cancelableArg, PassRefPtrWillBeRawPtr<AbstractView> viewArg, int detailArg)
+// TODO(lanwei): Will add sourceDevice to all the subclass of UIEvent later, see https://crbug.com/476530.
+UIEvent::UIEvent(const AtomicString& eventType, bool canBubbleArg, bool cancelableArg, PassRefPtrWillBeRawPtr<AbstractView> viewArg, int detailArg, InputDevice* sourceDeviceArg)
     : Event(eventType, canBubbleArg, cancelableArg)
     , m_view(viewArg)
     , m_detail(detailArg)
-    , m_sourceDevice(nullptr)
+    , m_sourceDevice(sourceDeviceArg)
 {
 }
 
 UIEvent::UIEvent(const AtomicString& eventType, const UIEventInit& initializer)
     : Event(eventType, initializer)
     , m_view(initializer.view())
     , m_detail(initializer.detail())
     , m_sourceDevice(initializer.sourceDevice())
 {
 }
@@ skipping 60 matching lines @@
 }
 
 DEFINE_TRACE(UIEvent)
 {
     visitor->trace(m_view);
     visitor->trace(m_sourceDevice);
     Event::trace(visitor);
 }
 
 } // namespace blink