Removed |which| from KeyboardEvent and MouseEvent.

third_party/WebKit/Source/core/events/MouseEvent.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 95 matching lines @@
   Node* toElement() const;
   Node* fromElement() const;
 
   virtual DataTransfer* getDataTransfer() const { return nullptr; }
 
   bool FromTouch() const { return synthetic_event_type_ == kFromTouch; }
 
   const AtomicString& InterfaceName() const override;
 
   bool IsMouseEvent() const override;
-  int which() const final;
+  unsigned which() const override;
 
   EventDispatchMediator* CreateMediator() override;
 
   int ClickCount() { return detail(); }
 
   const WebMouseEvent* NativeEvent() const { return native_event_.get(); }
 
   enum class PositionType {
     kPosition,
     // Positionless mouse events are used, for example, for 'click' events from
@@ skipping 144 matching lines @@
   MouseEvent& Event() const;
 
   DispatchEventResult DispatchEvent(EventDispatcher&) const override;
 };
 
 DEFINE_EVENT_TYPE_CASTS(MouseEvent);
 
 }  // namespace blink
 
 #endif  // MouseEvent_h