Fix broken AttachContext from r152289

Source/core/dom/NodeRenderingContext.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Google Inc. 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
@@ skipping 228 matching lines @@
 }
 
 void NodeRenderingContext::createRendererForElementIfNeeded()
 {
     ASSERT(!m_node->renderer());
 
     Element* element = toElement(m_node);
 
     if (!shouldCreateRenderer())
         return;
-    m_style = element->styleForRenderer();
+    if (!m_style)
+        m_style = element->styleForRenderer();
     ASSERT(m_style);
 
     moveToFlowThreadIfNeeded();
 
     if (!element->rendererIsNeeded(*this))
         return;
 
     RenderObject* parentRenderer = this->parentRenderer();
     RenderObject* nextRenderer = this->nextRenderer();
 
@@ skipping 57 matching lines @@
     newRenderer->setFlowThreadState(parentRenderer->flowThreadState());
 
     RenderObject* nextRenderer = this->nextRenderer();
     textNode->setRenderer(newRenderer);
     // Parent takes care of the animations, no need to call setAnimatableStyle.
     newRenderer->setStyle(m_style.release());
     parentRenderer->addChild(newRenderer, nextRenderer);
 }
 
 }