Make navigator.serviceWorker.ready resolve with the controller.

Source/modules/serviceworkers/ServiceWorkerContainer.idl

Index: Source/modules/serviceworkers/ServiceWorkerContainer.idl
diff --git a/Source/modules/serviceworkers/ServiceWorkerContainer.idl b/Source/modules/serviceworkers/ServiceWorkerContainer.idl
index d7b7638f36e4e75144f382e3ee884ece37468638..996f8bba8cd5fee1760a046a4cbaec7ea341135c 100644
--- a/Source/modules/serviceworkers/ServiceWorkerContainer.idl
+++ b/Source/modules/serviceworkers/ServiceWorkerContainer.idl
@@ -31,8 +31,10 @@
 [
     RuntimeEnabled=ServiceWorker
 ] interface ServiceWorkerContainer {
+    readonly attribute ServiceWorker controller;
+
+    [CallWith=ScriptState] readonly attribute Promise ready;
+
     [CallWith=ScriptState, ImplementedAs=registerServiceWorker] Promise register(DOMString url, optional Dictionary options);
     [CallWith=ScriptState, ImplementedAs=unregisterServiceWorker] Promise unregister(optional DOMString scope);
-
-    readonly attribute ServiceWorker controller;
 };