Implementation of CSS3 nav-up/down/left/right properties from CSS3 UI.

Source/core/rendering/style/RenderStyleConstants.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 139 matching lines @@
 enum BackgroundEdgeOrigin { TopEdge, RightEdge, BottomEdge, LeftEdge };
 
 // CSS Mask Source Types
 enum EMaskSourceType { MaskAlpha, MaskLuminance };
 
 // CSS3 Marquee Properties
 
 enum EMarqueeBehavior { MNONE, MSCROLL, MSLIDE, MALTERNATE };
 enum EMarqueeDirection { MAUTO = 0, MLEFT = 1, MRIGHT = -1, MUP = 2, MDOWN = -2, MFORWARD = 3, MBACKWARD = -3 };
 
+// CSS3 Directional Focus Navigation
+
+enum ENavigationTarget { Current = 0, Root = 1, TargetName = 2 };

[fs, 2014/10/01 10:52:14]

I think you can drop the explicit values, because AFAICS you don't rely on them
in any way.

+
 // Deprecated Flexible Box Properties
 
 enum EBoxPack { Start, Center, End, Justify };
 enum EBoxAlignment { BSTRETCH, BSTART, BCENTER, BEND, BBASELINE };
 enum EBoxOrient { HORIZONTAL, VERTICAL };
 enum EBoxLines { SINGLE, MULTIPLE };
 enum EBoxDirection { BNORMAL, BREVERSE };
 
 // CSS3 Flexbox Properties
 
@@ skipping 378 matching lines @@
 static const float maximumAllowedFontSize = 1000000.0f;
 
 enum TextIndentLine { TextIndentFirstLine, TextIndentEachLine };
 enum TextIndentType { TextIndentNormal, TextIndentHanging };
 
 enum CSSBoxType { BoxMissing = 0, MarginBox, BorderBox, PaddingBox, ContentBox };
 
 } // namespace blink
 
 #endif // RenderStyleConstants_h