Add support for the object-position CSS property.

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 436 matching lines @@
     case CSSPropertyMarginTop:
     case CSSPropertyMask:
     case CSSPropertyMaskType:
     case CSSPropertyMaskSourceType:
     case CSSPropertyMaxHeight:
     case CSSPropertyMaxWidth:
     case CSSPropertyMinHeight:
     case CSSPropertyMinWidth:
     case CSSPropertyMixBlendMode:
     case CSSPropertyObjectFit:
+    case CSSPropertyObjectPosition:
     case CSSPropertyOpacity:
     case CSSPropertyOutline:
     case CSSPropertyOutlineColor:
     case CSSPropertyOutlineOffset:
     case CSSPropertyOutlineStyle:
     case CSSPropertyOutlineWidth:
     case CSSPropertyOverflow:
     case CSSPropertyOverflowWrap:
     case CSSPropertyOverflowX:
     case CSSPropertyOverflowY:
@@ skipping 210 matching lines @@
         return false;
     case CSSPropertyInvalid:
         ASSERT_NOT_REACHED();
         return false;
     }
     ASSERT_NOT_REACHED();
     return false;
 }
 
 } // namespace WebCore