Support 'paint-order' from SVG2.

Source/core/css/CSSProperty.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 661 matching lines @@
     case CSSPropertyFloodOpacity:
     case CSSPropertyLightingColor:
     case CSSPropertyStopColor:
     case CSSPropertyStopOpacity:
     case CSSPropertyColorProfile:
     case CSSPropertyAlignmentBaseline:
     case CSSPropertyBaselineShift:
     case CSSPropertyDominantBaseline:
     case CSSPropertyVectorEffect:
     case CSSPropertyBufferedRendering:
+    case CSSPropertyPaintOrder:
     case CSSPropertyWebkitSvgShadow:
 #endif
     case CSSPropertyWebkitAppRegion:
 #if ENABLE(CSS_DEVICE_ADAPTATION)
     case CSSPropertyMaxZoom:
     case CSSPropertyMinZoom:
     case CSSPropertyOrientation:
     case CSSPropertyUserZoom:
 #endif
         return false;
     case CSSPropertyInvalid:
         ASSERT_NOT_REACHED();
         return false;
     }
     ASSERT_NOT_REACHED();
     return false;
 }
 
 void CSSProperty::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::CSS);
     info.addMember(m_value, "value");
     info.ignoreMember(m_metadata);
 }
 
 } // namespace WebCore