Remove the default wheel event handler from blink.

third_party/WebKit/Source/core/input/EventHandler.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010, 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 132 matching lines @@
     // Performs a logical scroll that chains, crossing frames, starting from
     // the given node or a reasonable default (focus/last clicked).
     bool bubblingScroll(ScrollDirection, ScrollGranularity, Node* startingNode = nullptr);
 
     WebInputEventResult handleMouseMoveEvent(const PlatformMouseEvent&);
     void handleMouseLeaveEvent(const PlatformMouseEvent&);
 
     WebInputEventResult handleMousePressEvent(const PlatformMouseEvent&);
     WebInputEventResult handleMouseReleaseEvent(const PlatformMouseEvent&);
     WebInputEventResult handleWheelEvent(const PlatformWheelEvent&);
-    void defaultWheelEventHandler(Node*, WheelEvent*);
 
     // Called on the local root frame exactly once per gesture event.
     WebInputEventResult handleGestureEvent(const PlatformGestureEvent&);
     WebInputEventResult handleGestureEvent(const GestureEventWithHitTestResults&);
 
     // Clear the old hover/active state within frames before moving the hover state to the another frame
     void updateGestureHoverActiveState(const HitTestRequest&, Element*);
 
     // Hit-test the provided (non-scroll) gesture event, applying touch-adjustment and updating
     // hover/active state across all frames if necessary. This should be called at most once
@@ skipping 214 matching lines @@
     bool m_longTapShouldInvokeContextMenu;
 
     Timer<EventHandler> m_activeIntervalTimer;
     double m_lastShowPressTimestamp;
     Member<Element> m_lastDeferredTapElement;
 };
 
 } // namespace blink
 
 #endif // EventHandler_h