div with overflow:hidden scrolls when dragging in a text box

Source/core/rendering/RenderLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 1342 matching lines @@
 {
     RenderLayer* curr = parent();
     while (curr && !isPositionedContainer(curr))
         curr = curr->parent();
 
     return curr;
 }
 
 RenderLayer* RenderLayer::enclosingScrollableLayer() const
 {
-    for (RenderObject* nextRenderer = renderer()->parent(); nextRenderer; nextRenderer = nextRenderer->parent()) {
-        if (nextRenderer->isBox() && toRenderBox(nextRenderer)->canBeScrolledAndHasScrollableArea())
-            return nextRenderer->enclosingLayer();
+    for (RenderLayer* nextLayer = parent(); nextLayer; nextLayer = nextLayer->parent()) {
+        if (nextLayer->renderer()->isBox() && toRenderBox(nextLayer->renderer())->canBeScrolledAndHasScrollableArea())
+            return nextLayer;
     }
 
     return 0;
 }
 
 IntRect RenderLayer::scrollableAreaBoundingBox() const
 {
     return renderer()->absoluteBoundingBoxRect();
 }
 
@@ skipping 909 matching lines @@
                         parentLayer = 0;
                 }
             } else {
                 LayoutRect viewRect = frameView->visibleContentRect();
                 LayoutRect r = getRectToExpose(viewRect, rect, alignX, alignY);
                 frameView->setScrollPosition(roundedIntPoint(r.location()));
             }
         }
     }
 
+    if (renderer()->frame()->page()->autoscrollInProgress())
+        parentLayer = enclosingScrollableLayer();
+
     if (parentLayer)
         parentLayer->scrollRectToVisible(newRect, alignX, alignY);
 
     if (frameView)
         frameView->resumeScheduledEvents();
 }
 
 void RenderLayer::updateCompositingLayersAfterScroll()
 {
     if (compositor()->inCompositingMode()) {
@@ skipping 4004 matching lines @@
     }
 }
 
 void showLayerTree(const WebCore::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif