Merge 78431 - Some Scrollbar functions assume an attached ScrollableArea but ...

Source/WebCore/platform/Scrollbar.cpp

 /*
  * Copyright (C) 2004, 2006, 2008 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 178 matching lines @@
         return;
 
     // Handle the track.
     if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && thumbUnderMouse(this)) {
         theme()->invalidatePart(this, m_pressedPart);
         setHoveredPart(ThumbPart);
         return;
     }
 
     // Handle the arrows and track.
-    if (scrollableArea()->scroll(pressedPartScrollDirection(), pressedPartScrollGranularity()))
+    if (m_scrollableArea && m_scrollableArea->scroll(pressedPartScrollDirection(), pressedPartScrollGranularity()))
         startTimerIfNeeded(delay);
 }
 
 void Scrollbar::startTimerIfNeeded(double delay)
 {
     // Don't do anything for the thumb.
     if (m_pressedPart == ThumbPart)
         return;
 
     // Handle the track.  We halt track scrolling once the thumb is level
@@ skipping 51 matching lines @@
     int trackLen = theme()->trackLength(this);
     int maxPos = trackLen - thumbLen;
     int delta = pos - m_pressedPos;
     if (delta > 0)
         delta = min(maxPos - thumbPos, delta);
     else if (delta < 0)
         delta = max(-thumbPos, delta);
     
     if (delta) {
         float newPosition = static_cast<float>(thumbPos + delta) * maximum() / (trackLen - thumbLen);
-        scrollableArea()->scrollToOffsetWithoutAnimation(m_orientation, newPosition);
+        if (m_scrollableArea)
+            m_scrollableArea->scrollToOffsetWithoutAnimation(m_orientation, newPosition);
     }
 }
 
 void Scrollbar::setHoveredPart(ScrollbarPart part)
 {
     if (part == m_hoveredPart)
         return;
 
     if ((m_hoveredPart == NoPart || part == NoPart) && theme()->invalidateOnMouseEnterExit())
         invalidate();  // Just invalidate the whole scrollbar, since the buttons at either end change anyway.
@@ skipping 11 matching lines @@
     m_pressedPart = part;
     if (m_pressedPart != NoPart)
         theme()->invalidatePart(this, m_pressedPart);
     else if (m_hoveredPart != NoPart)  // When we no longer have a pressed part, we can start drawing a hovered state on the hovered part.
         theme()->invalidatePart(this, m_hoveredPart);
 }
 
 bool Scrollbar::mouseMoved(const PlatformMouseEvent& evt)
 {
     if (m_pressedPart == ThumbPart) {
-        if (theme()->shouldSnapBackToDragOrigin(this, evt))
-            scrollableArea()->scrollToOffsetWithoutAnimation(m_orientation, m_dragOrigin);
-        else {
+        if (theme()->shouldSnapBackToDragOrigin(this, evt)) {
+            if (m_scrollableArea)
+                m_scrollableArea->scrollToOffsetWithoutAnimation(m_orientation, m_dragOrigin);
+        } else {
             moveThumb(m_orientation == HorizontalScrollbar ? 
                       convertFromContainingWindow(evt.pos()).x() :
                       convertFromContainingWindow(evt.pos()).y());
         }
         return true;
     }
 
     if (m_pressedPart != NoPart)
         m_pressedPos = (orientation() == HorizontalScrollbar ? convertFromContainingWindow(evt.pos()).x() : convertFromContainingWindow(evt.pos()).y());
 
@@ skipping 163 matching lines @@
 
 IntPoint Scrollbar::convertFromContainingView(const IntPoint& parentPoint) const
 {
     if (m_scrollableArea)
         return m_scrollableArea->convertFromContainingViewToScrollbar(this, parentPoint);
 
     return Widget::convertFromContainingView(parentPoint);
 }
 
 } // namespace WebCore