Bug 1536468 - Make retrieval of WebBrowserPersistDocumentAttrs.cacheKey async in SessionHistory. Compilation fix, r=peterv.

--HG--
extra : rebase_source : 8321dc0a79106d203d14d57f439e493e2b42e0da
extra : source : 2709d418af1932b9bf0e6dc0826a9644766f354e
extra : histedit_source : 2646b25af17a6ef62e1b02ad8896139c3f6855e1

dom/webbrowserpersist/nsIWebBrowserPersistDocument.idl

@@ -54,7 +54,7 @@ interface nsIWebBrowserPersistURIMap : nsISupports
  * changes made to the underlying document; most of these are
  * self-explanatory from their names and types.
  */
-[scriptable, uuid(74aa4918-5d15-46b6-9ccf-74f9696d721d)]
+[scriptable, builtinclass, uuid(74aa4918-5d15-46b6-9ccf-74f9696d721d)]
 interface nsIWebBrowserPersistDocument : nsISupports
 {
   readonly attribute boolean isPrivate;