Cleanup namespace usage in public/web/Web[A-M]*.h.

public/web/WebDOMMouseEvent.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #ifndef WebDOMMouseEvent_h
 #define WebDOMMouseEvent_h
 
 #include "WebDOMEvent.h"
 
-#if BLINK_IMPLEMENTATION
-namespace blink { class Event; }
-#endif
-
 namespace blink {
 
 class WebDOMMouseEvent : public WebDOMEvent {
 public:
     BLINK_EXPORT int screenX() const;
     BLINK_EXPORT int screenY() const;
     BLINK_EXPORT int clientX() const;
     BLINK_EXPORT int clientY() const;
     BLINK_EXPORT int offsetX();
     BLINK_EXPORT int offsetY();
     BLINK_EXPORT int pageX() const;
     BLINK_EXPORT int pageY() const;
     BLINK_EXPORT int x() const;
     BLINK_EXPORT int y() const;
 
     BLINK_EXPORT int button() const;
     BLINK_EXPORT bool buttonDown() const;
 };
 
 } // namespace blink
 
 #endif