Avoid maybe-uninitialized gcc warning.

Source/core/dom/CharacterData.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 106 matching lines @@
     if (offsetCount.hasOverflowed() || offset + count > length)
         realCount = length - offset;
     else
         realCount = count;
 
     return true;
 }
 
 void CharacterData::deleteData(unsigned offset, unsigned count, ExceptionState& exceptionState, RecalcStyleBehavior recalcStyleBehavior)
 {
-    unsigned realCount;
+    unsigned realCount = 0;
     if (!validateOffsetCount(offset, count, length(), realCount, exceptionState))
         return;
 
     String newStr = m_data;
     newStr.remove(offset, realCount);
 
     setDataAndUpdate(newStr, offset, realCount, 0, recalcStyleBehavior);
 
     document().didRemoveText(this, offset, realCount);
 }
 
 void CharacterData::replaceData(unsigned offset, unsigned count, const String& data, ExceptionState& exceptionState)
 {
-    unsigned realCount;
+    unsigned realCount = 0;
     if (!validateOffsetCount(offset, count, length(), realCount, exceptionState))
         return;
 
     String newStr = m_data;
     newStr.remove(offset, realCount);
     newStr.insert(data, offset);
 
     setDataAndUpdate(newStr, offset, realCount, data.length());
 
     // update the markers for spell checking and grammar checking
@@ skipping 55 matching lines @@
 {
     return static_cast<int>(length());
 }
 
 bool CharacterData::offsetInCharacters() const
 {
     return true;
 }
 
 } // namespace WebCore