[trivial] Remove RenderBox::MarginSign

Source/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 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.
  *
@@ skipping 303 matching lines @@
     {
         const RenderStyle* styleToUse = overrideStyle ? overrideStyle : style();
         m_marginBox.setStart(styleToUse->writingMode(), styleToUse->direction(), value);
     }
     void setMarginEnd(LayoutUnit value, const RenderStyle* overrideStyle = 0)
     {
         const RenderStyle* styleToUse = overrideStyle ? overrideStyle : style();
         m_marginBox.setEnd(styleToUse->writingMode(), styleToUse->direction(), value);
     }
 
-    // The following five functions are used to implement collapsing margins.
+    // The following functions are used to implement collapsing margins.
     // All objects know their maximal positive and negative margins.  The
     // formula for computing a collapsed margin is |maxPosMargin| - |maxNegmargin|.
     // For a non-collapsing box, such as a leaf element, this formula will simply return
     // the margin of the element.  Blocks override the maxMarginBefore and maxMarginAfter
     // methods.
-    enum MarginSign { PositiveMargin, NegativeMargin };
     virtual bool isSelfCollapsingBlock() const { return false; }
     virtual LayoutUnit collapsedMarginBefore() const { return marginBefore(); }
     virtual LayoutUnit collapsedMarginAfter() const { return marginAfter(); }
 
     virtual void absoluteRects(Vector<IntRect>&, const LayoutPoint& accumulatedOffset) const OVERRIDE;
     virtual void absoluteQuads(Vector<FloatQuad>&, bool* wasFixed) const OVERRIDE;
 
     int reflectionOffset() const;
     // Given a rect in the object's coordinate space, returns the corresponding rect in the reflection.
     LayoutRect reflectedRect(const LayoutRect&) const;
@@ skipping 463 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // RenderBox_h