Add support for the object-position CSS property.

Source/core/rendering/style/RenderStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * 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.
  *
@@ skipping 594 matching lines @@
     if (inherited_flags._visibility != other->inherited_flags._visibility
         || inherited_flags.m_printColorAdjust != other->inherited_flags.m_printColorAdjust
         || inherited_flags._insideLink != other->inherited_flags._insideLink
         || surround->border != other->surround->border
         || *m_background.get() != *other->m_background.get()
         || rareInheritedData->userModify != other->rareInheritedData->userModify
         || rareInheritedData->userSelect != other->rareInheritedData->userSelect
         || rareNonInheritedData->userDrag != other->rareNonInheritedData->userDrag
         || rareNonInheritedData->m_borderFit != other->rareNonInheritedData->m_borderFit
         || rareNonInheritedData->m_objectFit != other->rareNonInheritedData->m_objectFit
+        || rareNonInheritedData->m_objectPosition != other->rareNonInheritedData->m_objectPosition
         || rareInheritedData->m_imageRendering != other->rareInheritedData->m_imageRendering)
         return StyleDifferenceRepaint;
 
         // FIXME: The current spec is being reworked to remove dependencies between exclusions and affected
         // content. There's a proposal to use floats instead. In that case, wrap-shape should actually relayout
         // the parent container. For sure, I will have to revisit this code, but for now I've added this in order
         // to avoid having diff() == StyleDifferenceEqual where wrap-shapes actually differ.
         // Tracking bug: https://bugs.webkit.org/show_bug.cgi?id=62991
         if (rareNonInheritedData->m_shapeOutside != other->rareNonInheritedData->m_shapeOutside)
             return StyleDifferenceRepaint;
@@ skipping 939 matching lines @@
     surround.access()->border.m_image.setOutset(outset);
 }
 
 ShapeValue* RenderStyle::initialShapeInside()
 {
     DEFINE_STATIC_LOCAL(RefPtr<ShapeValue>, sOutsideValue, (ShapeValue::createOutsideValue()));
     return sOutsideValue.get();
 }
 
 } // namespace WebCore