Selectively disable rubber banding on mac.

Source/platform/PlatformWheelEvent.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2009 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 55 matching lines @@
         , m_wheelTicksY(0)
         , m_granularity(ScrollByPixelWheelEvent)
         , m_directionInvertedFromDevice(false)
         , m_hasPreciseScrollingDeltas(false)
 #if OS(MACOSX)
         , m_phase(PlatformWheelEventPhaseNone)
         , m_momentumPhase(PlatformWheelEventPhaseNone)
         , m_scrollCount(0)
         , m_unacceleratedScrollingDeltaX(0)
         , m_unacceleratedScrollingDeltaY(0)
+        , m_canRubberbandLeft(true)
+        , m_canRubberbandRight(true)
 #endif
     {
     }
 
     PlatformWheelEvent(IntPoint position, IntPoint globalPosition, float deltaX, float deltaY, float wheelTicksX, float wheelTicksY, PlatformWheelEventGranularity granularity, bool shiftKey, bool ctrlKey, bool altKey, bool metaKey)
         : PlatformEvent(PlatformEvent::Wheel, shiftKey, ctrlKey, altKey, metaKey, 0)
         , m_position(position)
         , m_globalPosition(globalPosition)
         , m_deltaX(deltaX)
         , m_deltaY(deltaY)
         , m_wheelTicksX(wheelTicksX)
         , m_wheelTicksY(wheelTicksY)
         , m_granularity(granularity)
         , m_directionInvertedFromDevice(false)
         , m_hasPreciseScrollingDeltas(false)
 #if OS(MACOSX)
         , m_phase(PlatformWheelEventPhaseNone)
         , m_momentumPhase(PlatformWheelEventPhaseNone)
         , m_scrollCount(0)
         , m_unacceleratedScrollingDeltaX(0)
         , m_unacceleratedScrollingDeltaY(0)
+        , m_canRubberbandLeft(true)
+        , m_canRubberbandRight(true)
 #endif
     {
     }
 
     PlatformWheelEvent copyTurningVerticalTicksIntoHorizontalTicks() const
     {
         PlatformWheelEvent copy = *this;
 
         copy.m_deltaX = copy.m_deltaY;
         copy.m_deltaY = 0;
@@ skipping 18 matching lines @@
 
     bool hasPreciseScrollingDeltas() const { return m_hasPreciseScrollingDeltas; }
     void setHasPreciseScrollingDeltas(bool b) { m_hasPreciseScrollingDeltas = b; }
 #if OS(MACOSX)
     PlatformWheelEventPhase phase() const { return m_phase; }
     PlatformWheelEventPhase momentumPhase() const { return m_momentumPhase; }
     unsigned scrollCount() const { return m_scrollCount; }
     float unacceleratedScrollingDeltaX() const { return m_unacceleratedScrollingDeltaX; }
     float unacceleratedScrollingDeltaY() const { return m_unacceleratedScrollingDeltaY; }
     bool useLatchedEventNode() const { return m_momentumPhase == PlatformWheelEventPhaseBegan || m_momentumPhase == PlatformWheelEventPhaseChanged; }
+    bool canRubberbandLeft() const { return m_canRubberbandLeft; }
+    bool canRubberbandRight() const { return m_canRubberbandRight; }
 #else
     bool useLatchedEventNode() const { return false; }
 #endif
 
 protected:
     IntPoint m_position;
     IntPoint m_globalPosition;
     float m_deltaX;
     float m_deltaY;
     float m_wheelTicksX;
     float m_wheelTicksY;
     PlatformWheelEventGranularity m_granularity;
     bool m_directionInvertedFromDevice;
     bool m_hasPreciseScrollingDeltas;
 #if OS(MACOSX)
     PlatformWheelEventPhase m_phase;
     PlatformWheelEventPhase m_momentumPhase;
     unsigned m_scrollCount;
     float m_unacceleratedScrollingDeltaX;
     float m_unacceleratedScrollingDeltaY;
+    bool m_canRubberbandLeft;
+    bool m_canRubberbandRight;
 #endif
 };
 
 } // namespace WebCore
 
 #endif // PlatformWheelEvent_h