Removed |which| from KeyboardEvent and MouseEvent.

third_party/WebKit/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 52 matching lines @@
 
   AbstractView* view() const { return view_.Get(); }
   int detail() const { return detail_; }
   InputDeviceCapabilities* sourceCapabilities() const {
     return source_capabilities_.Get();
   }
 
   const AtomicString& InterfaceName() const override;
   bool IsUIEvent() const final;
 
-  virtual int which() const;
+  virtual unsigned which() const;
 
   DECLARE_VIRTUAL_TRACE();
 
  protected:
   UIEvent();
   UIEvent(const AtomicString& type,
           bool can_bubble,
           bool cancelable,
           ComposedMode,
           TimeTicks platform_time_stamp,
           AbstractView*,
           int detail,
           InputDeviceCapabilities* source_capabilities);
   UIEvent(const AtomicString&,
           const UIEventInit&,
           TimeTicks platform_time_stamp);
   UIEvent(const AtomicString& type, const UIEventInit& init)
       : UIEvent(type, init, TimeTicks::Now()) {}
 
  private:
   Member<AbstractView> view_;
   int detail_;
   Member<InputDeviceCapabilities> source_capabilities_;
 };
 
 }  // namespace blink
 
 #endif  // UIEvent_h