Remove special wheel handling path from ScrollableArea

Source/core/frame/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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
@@ skipping 289 matching lines @@
     const ScrollableAreaSet* animatingScrollableAreas() const { return m_animatingScrollableAreas.get(); }
 
     // With CSS style "resize:" enabled, a little resizer handle will appear at the bottom
     // right of the object. We keep track of these resizer areas for checking if touches
     // (implemented using Scroll gesture) are targeting the resizer.
     typedef HashSet<LayoutBox*> ResizerAreaSet;
     void addResizerArea(LayoutBox&);
     void removeResizerArea(LayoutBox&);
     const ResizerAreaSet* resizerAreas() const { return m_resizerAreas.get(); }
 
-    // This function exists for ports that need to handle wheel events manually.
-    // On Mac WebKit1 the underlying NSScrollView just does the scrolling, but on most other platforms
-    // we need this function in order to do the scroll ourselves.
-    ScrollResult wheelEvent(const PlatformWheelEvent&);
-
     bool shouldUseIntegerScrollOffset() const override;
 
     bool isActive() const override;
 
     // Override scrollbar notifications to update the AXObject cache.
     void didAddScrollbar(Scrollbar*, ScrollbarOrientation) override;
 
     // FIXME: This should probably be renamed as the 'inSubtreeLayout' parameter
     // passed around the FrameView layout methods can be true while this returns
     // false.
@@ skipping 539 matching lines @@
     static const unsigned visualPixelThreshold = 32 * 32;
     if (m_visuallyNonEmptyPixelCount > visualPixelThreshold)
         setIsVisuallyNonEmpty();
 }
 
 DEFINE_TYPE_CASTS(FrameView, Widget, widget, widget->isFrameView(), widget.isFrameView());
 
 } // namespace blink
 
 #endif // FrameView_h