Reduce forward declarations in core/rendering

Source/core/rendering/line/LineWidth.h

 /*
  * Copyright (C) 2013 Adobe Systems Incorporated. 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.
@@ skipping 17 matching lines @@
  */
 
 #ifndef LineWidth_h
 #define LineWidth_h
 
 #include "platform/LayoutUnit.h"
 
 namespace WebCore {
 
 class FloatingObject;
-class RenderBlock;
 class RenderObject;
 class RenderRubyRun;
 class RenderBlockFlow;
 
-struct LineSegment;
-
 enum IndentTextOrNot { DoNotIndentText, IndentText };
 
 class LineWidth {
 public:
     LineWidth(RenderBlockFlow&, bool isFirstLine, IndentTextOrNot shouldIndentText);
 
     bool fitsOnLine() const { return currentWidth() <= (m_availableWidth + LayoutUnit::epsilon()); }
     bool fitsOnLine(float extra) const { return currentWidth() + extra <= (m_availableWidth + LayoutUnit::epsilon()); }
 
     float currentWidth() const { return m_committedWidth + m_uncommittedWidth; }
@@ skipping 23 matching lines @@
     float m_left;
     float m_right;
     float m_availableWidth;
     bool m_isFirstLine;
     IndentTextOrNot m_shouldIndentText;
 };
 
 }
 
 #endif // LineWidth_h