Inroduce toSVGInlineTextBox, and use it.

Source/core/rendering/svg/SVGTextQuery.cpp

 /*
  * Copyright (C) Research In Motion Limited 2010-2012. 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 81 matching lines @@
         if (child->isInlineFlowBox()) {
             // Skip generated content.
             if (!child->renderer()->node())
                 continue;
 
             collectTextBoxesInFlowBox(static_cast<InlineFlowBox*>(child));
             continue;
         }
 
         if (child->isSVGInlineTextBox())
-            m_textBoxes.append(static_cast<SVGInlineTextBox*>(child));
+            m_textBoxes.append(toSVGInlineTextBox(child));
     }
 }
 
 bool SVGTextQuery::executeQuery(Data* queryData, ProcessTextFragmentCallback fragmentCallback) const
 {
     ASSERT(!m_textBoxes.isEmpty());
 
     unsigned processedCharacters = 0;
     unsigned textBoxCount = m_textBoxes.size();
 
@@ skipping 434 matching lines @@
         return -1;
 
     CharacterNumberAtPositionData data(position);
     if (!executeQuery(&data, &SVGTextQuery::characterNumberAtPositionCallback))
         return -1;
 
     return data.processedCharacters;
 }
 
 }