Merge 77549 - Scroll thumb jumps to top when resizing horizontally....

Source/WebCore/platform/ScrollView.cpp

 /*
  * Copyright (C) 2006, 2007, 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 532 matching lines @@
             m_verticalScrollbar->setSuppressInvalidation(false);
     }
 
     if (hasHorizontalScrollbar != (m_horizontalScrollbar != 0) || hasVerticalScrollbar != (m_verticalScrollbar != 0)) {
         frameRectsChanged();
         updateScrollCorner();
     }
 
     ScrollableArea::scrollToOffsetWithoutAnimation(FloatPoint(scroll.width() + m_scrollOrigin.x(), scroll.height() + m_scrollOrigin.y()));
 
+    // Make sure the scrollbar offsets are up to date.
+    if (m_horizontalScrollbar)
+        m_horizontalScrollbar->offsetDidChange();
+    if (m_verticalScrollbar)
+        m_verticalScrollbar->offsetDidChange();
+
     m_inUpdateScrollbars = false;
 }
 
 const int panIconSizeLength = 16;
 
 void ScrollView::scrollContents(const IntSize& scrollDelta)
 {
     if (!hostWindow())
         return;
 
@@ skipping 586 matching lines @@
 }
 
 bool ScrollView::platformIsOffscreen() const
 {
     return false;
 }
 
 #endif
 
 }