Oilpan: Replace RefPtrs to Node and its subclasses in core/dom/ with Oilpan transtion types.

Source/core/page/DragController.cpp

Index: Source/core/page/DragController.cpp
diff --git a/Source/core/page/DragController.cpp b/Source/core/page/DragController.cpp
index c9bf62090ba920feb6e81f198501d803a730953a..20ef9ff1dff493533eaaa2d05b33bf570896c559 100644
--- a/Source/core/page/DragController.cpp
+++ b/Source/core/page/DragController.cpp
@@ -171,8 +171,7 @@ static PassRefPtrWillBeRawPtr<DocumentFragment> documentFragmentFromDragData(Dra
                     if (title.isEmpty())
                         title = url;
                 }
-                RefPtr<Node> anchorText = document.createTextNode(title);
-                anchor->appendChild(anchorText);
+                anchor->appendChild(document.createTextNode(title));
                 RefPtrWillBeRawPtr<DocumentFragment> fragment = document.createDocumentFragment();
                 fragment->appendChild(anchor);
                 return fragment.release();