Bug 868266. Root the arguments list in nsObjectLoadingContent::LegacyCall. r=terrence

content/base/src/nsObjectLoadingContent.cpp

@@ -2875,6 +2875,7 @@ nsObjectLoadingContent::LegacyCall(JSContext* aCx,
   // Now wrap things up into the compartment of "obj"
   JSAutoCompartment ac(aCx, obj);
   nsTArray<JS::Value> args(aArguments);
+  JS::AutoArrayRooter rooter(aCx, args.Length(), args.Elements());
   for (JS::Value *arg = args.Elements(), *arg_end = arg + args.Length();
        arg != arg_end;
        ++arg) {