Remove unneeded constructor for CompositionUnderline

Source/core/editing/CompositionUnderline.h

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 20 matching lines @@
 namespace blink {
 
 struct CompositionUnderline {
     CompositionUnderline()
         : startOffset(0)
         , endOffset(0)
         , color(Color::transparent)
         , thick(false)
         , backgroundColor(Color::transparent) { }
 
-    // FIXME(huangs): remove this constructor.
-    CompositionUnderline(unsigned s, unsigned e, const Color& c, bool t)
-        : startOffset(s)
-        , endOffset(e)
-        , color(c)
-        , thick(t)
-        , backgroundColor(Color::transparent) { }
-
     CompositionUnderline(unsigned s, unsigned e, const Color& c, bool t, const Color& bc)
         : startOffset(s)
         , endOffset(e)
         , color(c)
         , thick(t)
         , backgroundColor(bc) { }
 
     unsigned startOffset;
     unsigned endOffset;
     Color color;
     bool thick;
     Color backgroundColor;
 };
 
 } // namespace blink
 
 #endif // CompositionUnderline_h