ServiceWorker: Add support for .skipWaiting and controllerchange event(2/3)

content/browser/service_worker/service_worker_registration.h

Index: content/browser/service_worker/service_worker_registration.h
diff --git a/content/browser/service_worker/service_worker_registration.h b/content/browser/service_worker/service_worker_registration.h
index b386eecfad3fa265444694eb99c850339b07ebc3..bb88e416064e9fad17d1a7bc816fa65a4ace8fd0 100644
--- a/content/browser/service_worker/service_worker_registration.h
+++ b/content/browser/service_worker/service_worker_registration.h
@@ -41,6 +41,8 @@ class CONTENT_EXPORT ServiceWorkerRegistration
         ServiceWorkerRegistration* registration) {}
     virtual void OnUpdateFound(
         ServiceWorkerRegistration* registration) {}
+    virtual void OnSkippedWaiting(
+        ServiceWorkerRegistration* registation) {}
   };
 
   ServiceWorkerRegistration(const GURL& pattern,
@@ -99,7 +101,8 @@ class CONTENT_EXPORT ServiceWorkerRegistration
 
   // Triggers the [[Activate]] algorithm when the currently active version
   // has no controllees. If there are no controllees at the time the method
-  // is called, activation is initiated immediately.
+  // is called or when version's skip waiting flag is set, activation is
+  // initiated immediately.
   void ActivateWaitingVersionWhenReady();
 
   // Triggers the [[ClearRegistration]] algorithm when the currently