ServiceWorker: More accurate StartWorker result and UMA

content/browser/service_worker/service_worker_version.h

Index: content/browser/service_worker/service_worker_version.h
diff --git a/content/browser/service_worker/service_worker_version.h b/content/browser/service_worker/service_worker_version.h
index ba13327cba9f5968928a0002b65e4e8e51592f41..ea3adfb958fa149ae8ccd3e47608db79c46682a5 100644
--- a/content/browser/service_worker/service_worker_version.h
+++ b/content/browser/service_worker/service_worker_version.h
@@ -286,6 +286,9 @@ class CONTENT_EXPORT ServiceWorkerVersion
   void ReportError(ServiceWorkerStatusCode status,
                    const std::string& status_message);
 
+  // Sets the status code to pass to StartWorker callbacks if start fails.
+  void SetStartWorkerStatusCode(ServiceWorkerStatusCode status);
+
   // Sets this version's status to REDUNDANT and deletes its resources.
   // The version must not have controllees.
   void Doom();
@@ -543,6 +546,12 @@ class CONTENT_EXPORT ServiceWorkerVersion
   std::vector<int> pending_skip_waiting_requests_;
   scoped_ptr<net::HttpResponseInfo> main_script_http_info_;
 
+  // The status when StartWorker was invoked. Used for UMA.
+  Status prestart_status_ = NEW;

[nhiroki, 2015/04/24 04:58:28]

How about binding "prestart status" to DidEnsureLiveRegistrationForStartWorker
and RecordStartWorkerResult, and then removing this field? This class already
has many states and I'd rather not add such fields more...

[falken, 2015/04/24 05:08:26]

I originally wanted to do this but there are RecordStartWorkerResult callsites
like in the dtor that aren't binded. I agree about the states, maybe there's
opportunities to split some of these out into helper classes later.

[nhiroki, 2015/04/24 05:23:57]

Oh... I see. Thank you for explanation. LGTM

+  // If not OK, the reason that StartWorker failed. Used for
+  // running |start_callbacks_|.
+  ServiceWorkerStatusCode start_worker_status_ = SERVICE_WORKER_OK;
+
   base::WeakPtrFactory<ServiceWorkerVersion> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerVersion);