Have ChildFrameDisconnector / ChildListMutationScope deal with references

Source/core/editing/markup.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009, 2010, 2011 Google Inc. All rights reserved.
  * Copyright (C) 2011 Igalia S.L.
  * Copyright (C) 2011 Motorola Mobility. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 1010 matching lines @@
             if (Node* firstChild = element->firstChild())
                 nextNode = firstChild;
             removeElementPreservingChildren(fragment, element);
         }
     }
     return fragment.release();
 }
 
 void replaceChildrenWithFragment(ContainerNode* container, PassRefPtr<DocumentFragment> fragment, ExceptionState& es)
 {
+    ASSERT(container);
     RefPtr<ContainerNode> containerNode(container);
 
-    ChildListMutationScope mutation(containerNode.get());
+    ChildListMutationScope mutation(*containerNode);
 
     if (!fragment->firstChild()) {
         containerNode->removeChildren();
         return;
     }
 
     if (containerNode->hasOneTextChild() && fragment->hasOneTextChild()) {
         toText(containerNode->firstChild())->setData(toText(fragment->firstChild())->data());
         return;
     }
 
     if (containerNode->hasOneChild()) {
         containerNode->replaceChild(fragment, containerNode->firstChild(), es);
         return;
     }
 
     containerNode->removeChildren();
     containerNode->appendChild(fragment, es);
 }
 
 void replaceChildrenWithText(ContainerNode* container, const String& text, ExceptionState& es)
 {
+    ASSERT(container);
     RefPtr<ContainerNode> containerNode(container);
 
-    ChildListMutationScope mutation(containerNode.get());
+    ChildListMutationScope mutation(*containerNode);
 
     if (containerNode->hasOneTextChild()) {
         toText(containerNode->firstChild())->setData(text);
         return;
     }
 
     RefPtr<Text> textNode = Text::create(containerNode->document(), text);
 
     if (containerNode->hasOneChild()) {
         containerNode->replaceChild(textNode.release(), containerNode->firstChild(), es);
         return;
     }
 
     containerNode->removeChildren();
     containerNode->appendChild(textNode.release(), es);
 }
 
 }