Service Worker: (Re-commit) Make ServiceWorkerRegistration.update() return a promise. (Blink 1/3)

public/platform/WebServiceWorkerRegistration.h

Index: public/platform/WebServiceWorkerRegistration.h
diff --git a/public/platform/WebServiceWorkerRegistration.h b/public/platform/WebServiceWorkerRegistration.h
index 53790805cf2833d0e2d71d629bfa72f71e610844..e73eb456d0bde48a42ae27ff924c35e8c7c5acab 100644
--- a/public/platform/WebServiceWorkerRegistration.h
+++ b/public/platform/WebServiceWorkerRegistration.h
@@ -18,6 +18,7 @@ class WebServiceWorkerRegistration {
 public:
     virtual ~WebServiceWorkerRegistration() { }
 
+    using WebServiceWorkerUpdateCallbacks = WebCallbacks<void, WebServiceWorkerError*>;
     using WebServiceWorkerUnregistrationCallbacks = WebCallbacks<bool*, WebServiceWorkerError*>;
 
     virtual void setProxy(WebServiceWorkerRegistrationProxy*) { }
@@ -25,7 +26,18 @@ public:
     virtual void proxyStopped() { }
 
     virtual WebURL scope() const { return WebURL(); }
+    // TODO(jungkees):
+    // void update(p) remains temporarily before the chromium-side companion
+    // patch lands: https://codereview.chromium.org/1270513002/.
+    // Before the chromium-side patch lands, the new update(p, c) will
+    // internally call update(provider) to work with the existing code base.
+    // The final changes will be incorporated with the Blink layout patches.
     virtual void update(WebServiceWorkerProvider*) { }
+    virtual void update(WebServiceWorkerProvider* provider, WebServiceWorkerUpdateCallbacks* callback)
+    {
+        update(provider);
+        callback->onSuccess();
+    }
     virtual void unregister(WebServiceWorkerProvider*, WebServiceWorkerUnregistrationCallbacks*) { }
 };