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

Source/core/rendering/InlineFlowBox.h

Index: Source/core/rendering/InlineFlowBox.h
diff --git a/Source/core/rendering/InlineFlowBox.h b/Source/core/rendering/InlineFlowBox.h
index e81e426f2eab971fde1f9d8c85cf4ec613aa4383..3ada554086019a982a50f835809d0aa87d74aa8a 100644
--- a/Source/core/rendering/InlineFlowBox.h
+++ b/Source/core/rendering/InlineFlowBox.h
@@ -317,11 +317,10 @@ protected:
     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;