Remove -webkit-line-box-contain implementation.

Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 1165 matching lines @@
         ASSERT(RuntimeEnabledFeatures::css3TextDecorationsEnabled());
         return true;
 
     // text-shadow added in text decoration spec:
     // http://www.w3.org/TR/css-text-decor-3/#text-shadow-property
     case CSSPropertyTextShadow:
     // box-shadox added in CSS3 backgrounds spec:
     // http://www.w3.org/TR/css3-background/#placement
     case CSSPropertyBoxShadow:
     // Properties that we currently support outside of spec.
-    case CSSPropertyWebkitLineBoxContain:
     case CSSPropertyVisibility:
         return true;
 
     default:
         return false;
     }
 }
 
 static bool shouldIgnoreTextTrackAuthorStyle(const Document& document)
 {
@@ skipping 340 matching lines @@
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingScopes);
     visitor->trace(m_styleResourceLoader);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);
     visitor->trace(m_document);
 #endif
 }
 
 } // namespace blink