Prerender: Confirm ServiceWorkers are invoked for NoState Prefetch

content/public/browser/service_worker_context.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_SERVICE_WORKER_CONTEXT_H_
 #define CONTENT_PUBLIC_BROWSER_SERVICE_WORKER_CONTEXT_H_
 
 #include <set>
 #include <string>
 
@@ skipping 107 matching lines @@
   // specified |origin| via |callback|.
   virtual void CountExternalRequestsForTest(
       const GURL& origin,
       const CountExternalRequestsCallback& callback) = 0;
 
   // Stops all running workers on the given |origin|.
   //
   // This function can be called from any thread.
   virtual void StopAllServiceWorkersForOrigin(const GURL& origin) = 0;
 
+  // As above, but |callback| is executed when a running worker is stopped. If
+  // there is no running worker, |callback| will never be executed.

[horo, 2017/01/05 05:33:58]

Please write comment that the |callback| is executed on the IO thread.

I think the |callback| should be executed when all workers are stopped.
And even if there is no worker we should execute |callback|.

[mattcary, 2017/01/05 14:30:43]

Done.

Note that the RunSoon helper defined in service_worker_context_wrapper.cc
doesn't check for the callback being null; is that worth adding or should I keep
the code as-is?

[horo, 2017/01/06 02:27:41]

The |callback| should be called only once when the "all" running workers are
stopped. Not "each".
Could you please change the code using BarrierClosure?
I don't think we need the null check.

[mattcary, 2017/01/06 15:21:22]

Ah, I misunderstood. That's a good idea, done.
done

+  virtual void StopAllServiceWorkersForOriginWithCallback(
+      const GURL& origin,
+      const base::Closure& callback) = 0;
+
   // Stops all running service workers and unregisters all service worker
   // registrations. This method is used in LayoutTests to make sure that the
   // existing service worker will not affect the succeeding tests.
   //
   // This function can be called from any thread, but the callback will always
   // be called on the UI thread.
   virtual void ClearAllServiceWorkersForTest(const base::Closure& callback) = 0;
 
   // Starts a Service Worker for |document_url| for a navigation hint in the
   // specified render process |render_process_id|. Must be called from the UI
   // thread. The |callback| will always be called on the UI thread.
   // This method can fail if:
   //  * No Service Worker was registered for |document_url|.
   //  * The specified render process is not suitable for loading |document_url|.
   virtual void StartServiceWorkerForNavigationHint(
       const GURL& document_url,
       blink::WebNavigationHintType type,
       int render_process_id,
       const ResultCallback& callback) = 0;
 
  protected:
   ServiceWorkerContext() {}
   virtual ~ServiceWorkerContext() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_SERVICE_WORKER_CONTEXT_H_