Selectively disable rubber banding on mac.

Source/web/WebInputEventConversion.cpp

 /*
  * Copyright (C) 2009 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 138 matching lines @@
         m_modifiers |= PlatformEvent::MetaKey;
 
     m_hasPreciseScrollingDeltas = e.hasPreciseScrollingDeltas;
 #if OS(MACOSX)
     m_phase = static_cast<WebCore::PlatformWheelEventPhase>(e.phase);
     m_momentumPhase = static_cast<WebCore::PlatformWheelEventPhase>(e.momentumPhase);
     m_timestamp = e.timeStampSeconds;
     m_scrollCount = 0;
     m_unacceleratedScrollingDeltaX = e.deltaX;
     m_unacceleratedScrollingDeltaY = e.deltaY;
+    m_canRubberbandLeft = e.canRubberbandLeft;
+    m_canRubberbandRight = e.canRubberbandRight;
 #endif
 }
 
 // PlatformGestureEventBuilder --------------------------------------------------
 
 PlatformGestureEventBuilder::PlatformGestureEventBuilder(Widget* widget, const WebGestureEvent& e)
 {
     float scale = widgetInputEventsScaleFactor(widget);
     IntSize offset = widgetInputEventsOffset(widget);
 
@@ skipping 595 matching lines @@
     modifiers = getWebInputModifiers(event);
 
     globalX = event.screenX();
     globalY = event.screenY();
     IntPoint localPoint = convertAbsoluteLocationForRenderObject(event.absoluteLocation(), *renderObject);
     x = localPoint.x();
     y = localPoint.y();
 }
 
 } // namespace blink