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

Source/WebCore/platform/ScrollView.cpp

Index: Source/WebCore/platform/ScrollView.cpp
===================================================================
--- Source/WebCore/platform/ScrollView.cpp	(revision 78241)
+++ Source/WebCore/platform/ScrollView.cpp	(working copy)
@@ -550,6 +550,12 @@
 
     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;
 }