Make navigator.serviceWorker.ready resolve with the controller.

Source/modules/serviceworkers/ServiceWorkerContainer.cpp

Index: Source/modules/serviceworkers/ServiceWorkerContainer.cpp
diff --git a/Source/modules/serviceworkers/ServiceWorkerContainer.cpp b/Source/modules/serviceworkers/ServiceWorkerContainer.cpp
index 8a2e6484a3d6e3517145bc8c814731f84e8b866c..db1d58c50849453cb2407ac75f58c31cae1d33fa 100644
--- a/Source/modules/serviceworkers/ServiceWorkerContainer.cpp
+++ b/Source/modules/serviceworkers/ServiceWorkerContainer.cpp
@@ -32,6 +32,7 @@
 
 #include "RuntimeEnabledFeatures.h"
 #include "bindings/v8/CallbackPromiseAdapter.h"
+#include "bindings/v8/ScriptPromise.h"
 #include "bindings/v8/ScriptPromiseResolverWithContext.h"
 #include "bindings/v8/ScriptState.h"
 #include "bindings/v8/SerializedScriptValue.h"
@@ -141,6 +142,19 @@ ScriptPromise ServiceWorkerContainer::unregisterServiceWorker(ScriptState* scrip
     return promise;
 }
 
+ScriptPromise ServiceWorkerContainer::ready(ScriptState* scriptState)
+{
+    if (m_controller.get()) {
+        RefPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+        ScriptPromise promise = resolver->promise();
+        resolver->resolve(m_controller.get());
+        return promise;
+    }
+    // FIXME: Elaborate the implementation when the "waiting" property
+    // or replace() is implemented.
+    return ScriptPromise();
+}
+
 void ServiceWorkerContainer::setCurrentServiceWorker(blink::WebServiceWorker* serviceWorker)
 {
     setController(serviceWorker);