Makes sure RenderableComposite resolves PotentialElement.

Review at http://gwt-code-reviews.appspot.com/1447819


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10284 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/src/com/google/gwt/user/client/ui/RenderableComposite.java b/user/src/com/google/gwt/user/client/ui/RenderableComposite.java
index cfb36a2..fae9b06 100644
--- a/user/src/com/google/gwt/user/client/ui/RenderableComposite.java
+++ b/user/src/com/google/gwt/user/client/ui/RenderableComposite.java
@@ -213,7 +213,7 @@
   private void initWidgetInternal() {
     // Use the contained widget's element as the composite's element,
     // effectively merging them within the DOM.
-    setElement(widget.getElement());
+    setElement(PotentialElement.resolve(widget.getElement()));
 
     // Adopt.
     widget.setParent(this);