CustomScrollbar Style not updated for IFrame.

Source/core/rendering/RenderPart.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  *           (C) 2000 Stefan Schimanski (1Stein@gmx.de)
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 191 matching lines @@
 }
 
 void RenderPart::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
 {
     RenderReplaced::styleDidChange(diff, oldStyle);
     Widget* widget = this->widget();
 
     if (!widget)
         return;
 
+    // If the iframe has custom scrollbars, recalculate their style.
+    if (widget && widget->isFrameView())
+        toFrameView(widget)->recalculateCustomScrollbarStyle();
+
     if (style()->visibility() != VISIBLE) {
         widget->hide();
     } else {
         widget->show();
     }
 }
 
 void RenderPart::layout()
 {
     ASSERT(needsLayout());
@@ skipping 103 matching lines @@
     if (widget->frameRect() == newFrame)
         return false;
 
     RefPtrWillBeRawPtr<RenderPart> protector(this);
     RefPtrWillBeRawPtr<Node> protectedNode(node());
     widget->setFrameRect(newFrame);
     return widget->frameRect().size() != newFrame.size();
 }
 
 }