ServiceWorker: add ServiceWorkerClients.claim() support (2/3).

content/browser/service_worker/service_worker_provider_host.h

Index: content/browser/service_worker/service_worker_provider_host.h
diff --git a/content/browser/service_worker/service_worker_provider_host.h b/content/browser/service_worker/service_worker_provider_host.h
index 9123014273d400004148f897a6ed999799677d5b..1be9086f3f2888b3fcf22bf5afe12e411c05d556 100644
--- a/content/browser/service_worker/service_worker_provider_host.h
+++ b/content/browser/service_worker/service_worker_provider_host.h
@@ -94,6 +94,10 @@ class CONTENT_EXPORT ServiceWorkerProviderHost
   void SetTopmostFrameUrl(const GURL& url);
   const GURL& topmost_frame_url() const { return topmost_frame_url_; }
 
+  // Starts using the |registration| which means the active worker will
+  // control this provider.
+  void UseRegistration(ServiceWorkerRegistration* registration);

[falken, 2015/01/28 08:59:49]

This is better, but I'm still not a fan of this name. The user of this class
will likely be unsure when to use UseRegistration or AssociateRegistration.

I like Michael's suggestion:
- "first rejigger the associated registrations" (AssociateRegistration)
- "then notify them of the being claimed by a new version"
(OnClaimedByNewVersion)

[xiang, 2015/01/29 02:58:37]

You are right, the "use" will confuse people without the spec context. I will
change it.
The OnClaimedByNewVersion() seems not needed, if we make a "claiming" flag in
version.

+
   // Associates to |registration| to listen for its version change events.

[falken, 2015/01/28 08:59:49]

It's not part of your patch, but this class no longer listens for version change
events.

   void AssociateRegistration(ServiceWorkerRegistration* registration);