Bug 985812 - Make a ActivityRequestHandler.source a pure cached frozen dictionary; r=bzbarsky

dom/activities/src/ActivityRequestHandler.js

@@ -42,6 +42,9 @@ ActivityRequestHandler.prototype = {
   },
 
   get source() {
+    // We need to clone this object because the this._options.data has
+    // the type any in WebIDL which will cause the binding layer to pass
+    // the value which is a COW unmodified to content.
     return Cu.cloneInto(this._options, this._window);
   },
 

dom/webidl/ActivityRequestHandler.webidl

@@ -10,5 +10,6 @@ interface ActivityRequestHandler
 {
     void postResult(any result);
     void postError(DOMString error);
-    readonly attribute object source;
+    [Pure, Cached, Frozen]
+    readonly attribute ActivityOptions source;
 };