Stop explicit inheritance if LayoutStyle doesn't change.

Source/core/layout/style/LayoutStyle.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, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * 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
@@ skipping 209 matching lines @@
                 && pageBreakBefore == other.pageBreakBefore
                 && pageBreakAfter == other.pageBreakAfter
                 && pageBreakInside == other.pageBreakInside
                 && styleType == other.styleType
                 && affectedByFocus == other.affectedByFocus
                 && affectedByHover == other.affectedByHover
                 && affectedByActive == other.affectedByActive
                 && affectedByDrag == other.affectedByDrag
                 && pseudoBits == other.pseudoBits
                 && unicodeBidi == other.unicodeBidi
-                && explicitInheritance == other.explicitInheritance

[esprehn, 2015/02/13 02:29:13]

This doesn't seem right, why is it okay to return == for a style where the
explicitInheritance bit doesn't match?

                 && unique == other.unique
                 && emptyState == other.emptyState
                 && isLink == other.isLink;
         }
 
         bool operator!=(const NonInheritedFlags& other) const { return !(*this == other); }
 
         unsigned effectiveDisplay : 5; // EDisplay
         unsigned originalDisplay : 5; // EDisplay
         unsigned overflowX : 3; // EOverflow
@@ skipping 1610 matching lines @@
 }
 
 inline bool LayoutStyle::hasPseudoElementStyle() const
 {
     return noninherited_flags.pseudoBits & PSEUDO_ELEMENT_MASK;
 }
 
 } // namespace blink
 
 #endif // LayoutStyle_h