Replace compile flag with runtime check for text-underline-position

Source/core/rendering/InlineFlowBox.h

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2007 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 299 matching lines @@
     OwnPtr<RenderOverflow> m_overflow;
 
     virtual bool isInlineFlowBox() const OVERRIDE FINAL { return true; }
 
     InlineBox* m_firstChild;
     InlineBox* m_lastChild;
 
     InlineFlowBox* m_prevLineBox; // The previous box that also uses our RenderObject
     InlineFlowBox* m_nextLineBox; // The next box that also uses our RenderObject
 
-#if ENABLE(CSS3_TEXT)
     // Maximum logicalTop among all children of an InlineFlowBox. Used to
     // calculate the offset for TextUnderlinePositionUnder.
     void computeMaxLogicalTop(float& maxLogicalTop) const;
-#endif // CSS3_TEXT
+
 private:
     unsigned m_includeLogicalLeftEdge : 1;
     unsigned m_includeLogicalRightEdge : 1;
     unsigned m_hasTextChildren : 1;
     unsigned m_hasTextDescendants : 1;
     unsigned m_descendantsHaveSameLineHeightAndBaseline : 1;
 
 protected:
     // The following members are only used by RootInlineBox but moved here to keep the bits packed.
 
@@ skipping 45 matching lines @@
 }
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const WebCore::InlineFlowBox*);
 #endif
 
 #endif // InlineFlowBox_h