Bug 1058901 - Disable ActivityRequestHandler in prerendering; r=jst

--HG--
extra : amend_source : 16f2cdec1408a17c071567b98c6072ebd4246eef

dom/webidl/ActivityRequestHandler.webidl

@@ -8,7 +8,9 @@
  ChromeOnly]
 interface ActivityRequestHandler
 {
+    [UnsafeInPrerendering]
     void postResult(any result);
+    [UnsafeInPrerendering]
     void postError(DOMString error);
     [Pure, Cached, Frozen]
     readonly attribute ActivityOptions source;