Move WebMouseWheelEvent into its own header file.

ui/events/blink/web_input_event_builders_win.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_EVENTS_BLINK_WEB_INPUT_EVENT_BUILDERS_WIN_H_
 #define UI_EVENTS_BLINK_WEB_INPUT_EVENT_BUILDERS_WIN_H_
 
 #include <windows.h>
 
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
+#include "third_party/WebKit/public/platform/WebMouseWheelEvent.h"
 
 namespace ui {
 
 class WebKeyboardEventBuilder {
  public:
   static blink::WebKeyboardEvent Build(HWND hwnd,
                                        UINT message,
                                        WPARAM wparam,
                                        LPARAM lparam,
                                        double time_stamp);
@@ skipping 17 matching lines @@
       UINT message,
       WPARAM wparam,
       LPARAM lparam,
       double time_stamp,
       blink::WebPointerProperties::PointerType pointer_type);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_BLINK_WEB_INPUT_EVENT_BUILDERS_WIN_H_