[CSS Regions] Elements in a region should be assignable to a named flow

Source/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. 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
@@ skipping 231 matching lines @@
     virtual RenderBlock* firstLineBlock() const;
 
     // Called when an object that was floating or positioned becomes a normal flow object
     // again.  We have to make sure the render tree updates as needed to accommodate the new
     // normal flow object.
     void handleDynamicFloatPositionChange();
     
     // RenderObject tree manipulation
     //////////////////////////////////////////
     virtual bool canHaveChildren() const { return virtualChildren(); }
+    virtual bool canDOMChildrenHaveRenderParent() const { return false; } // Even if this render object can't have render children, the children in the DOM tree may have a render parent (that is different from this object).
     virtual bool canHaveGeneratedChildren() const;
     virtual bool isChildAllowed(RenderObject*, RenderStyle*) const { return true; }
     virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0);
     virtual void addChildIgnoringContinuation(RenderObject* newChild, RenderObject* beforeChild = 0) { return addChild(newChild, beforeChild); }
     virtual void removeChild(RenderObject*);
     virtual bool createsAnonymousWrapper() const { return false; }
     //////////////////////////////////////////
 
     virtual void reportMemoryUsage(MemoryObjectInfo*) const;
 
@@ skipping 1069 matching lines @@
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const WebCore::RenderObject*);
 void showLineTree(const WebCore::RenderObject*);
 void showRenderTree(const WebCore::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const WebCore::RenderObject* object1, const WebCore::RenderObject* object2);
 #endif
 
 #endif // RenderObject_h