[oilpan] Handlify childrenChanged.

Source/core/dom/ContainerNode.h

Index: Source/core/dom/ContainerNode.h
diff --git a/Source/core/dom/ContainerNode.h b/Source/core/dom/ContainerNode.h
index f9ddbc5fe74e38b8504cb1f4f25ef58d45b47546..9eb9db6876183e03ce36a8cd1a4e9cbb7ca68a55 100644
--- a/Source/core/dom/ContainerNode.h
+++ b/Source/core/dom/ContainerNode.h
@@ -123,7 +123,7 @@ public:
 
     // Notifies the node that it's list of children have changed (either by adding or removing child nodes), or a child
     // node that is of the type CDATA_SECTION_NODE, TEXT_NODE or COMMENT_NODE has changed its value.
-    virtual void childrenChanged(bool createdByParser = false, Node* beforeChange = 0, Node* afterChange = 0, int childCountDelta = 0);
+    virtual void childrenChanged(bool createdByParser = false, const Handle<Node>& beforeChange = nullptr, const Handle<Node>& afterChange = nullptr, int childCountDelta = 0);
 
     void attachChildren();
     void attachChildrenLazily();