add 'slow' prefix to RenderObject's firstChild() / lastChild() methods

Source/core/editing/TextIterator.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 731 matching lines @@
         handleTextBox();
     }
 }
 
 static inline RenderText* firstRenderTextInFirstLetter(RenderObject* firstLetter)
 {
     if (!firstLetter)
         return 0;
 
     // FIXME: Should this check descendent objects?
-    for (RenderObject* current = firstLetter->firstChild(); current; current = current->nextSibling()) {
+    for (RenderObject* current = firstLetter->slowFirstChild(); current; current = current->nextSibling()) {
         if (current->isText())
             return toRenderText(current);
     }
     return 0;
 }
 
 void TextIterator::handleTextNodeFirstLetter(RenderTextFragment* renderer)
 {
     if (renderer->firstLetter()) {
         RenderObject* r = renderer->firstLetter();
@@ skipping 1432 matching lines @@
             resultEnd = collapseTo;
             return;
         }
     }
 
     CharacterIterator computeRangeIterator(inputStart, inputEnd, iteratorFlagsForFindPlainText);
     calculateCharacterSubrange(computeRangeIterator, matchStart, matchLength, resultStart, resultEnd);
 }
 
 }