Fix integer overflow in ComputedStyle::computedLineHeight

Source/core/style/ComputedStyle.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * 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 570 matching lines @@
 
     float zoom() const { return visual->m_zoom; }
     float effectiveZoom() const { return rareInheritedData->m_effectiveZoom; }
 
     TextDirection direction() const { return static_cast<TextDirection>(inherited_flags._direction); }
     bool isLeftToRightDirection() const { return direction() == LTR; }
     bool selfOrAncestorHasDirAutoAttribute() const { return rareInheritedData->m_selfOrAncestorHasDirAutoAttribute; }
 
     const Length& specifiedLineHeight() const;
     Length lineHeight() const;
-    int computedLineHeight() const;
+    LayoutUnit computedLineHeight() const;
 
     EWhiteSpace whiteSpace() const { return static_cast<EWhiteSpace>(inherited_flags._white_space); }
     static bool autoWrap(EWhiteSpace ws)
     {
         // Nowrap and pre don't automatically wrap.
         return ws != NOWRAP && ws != PRE;
     }
 
     bool autoWrap() const
     {
@@ skipping 1272 matching lines @@
 }
 
 inline bool ComputedStyle::hasPseudoElementStyle() const
 {
     return noninherited_flags.pseudoBits & PSEUDO_ELEMENT_MASK;
 }
 
 } // namespace blink
 
 #endif // ComputedStyle_h