Prevent a service worker from keeping itself alive by self postMessage.

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 bbebd9e8c9f5036bf0000d6b7aa74389f5fb10ab..8c7c6ee124cec798e372821dec0d77ccdf8c170f 100644
--- a/content/browser/service_worker/service_worker_version.h
+++ b/content/browser/service_worker/service_worker_version.h
@@ -413,6 +413,12 @@ class CONTENT_EXPORT ServiceWorkerVersion
     return external_request_uuid_to_request_id_.size();
   }
 
+  // Returns the amount of time left until the request with the latest
+  // expiration time expires.
+  base::TimeDelta remaining_timeout() const {
+    return max_request_expiration_time_ - tick_clock_->NowTicks();
+  }
+
  private:
   friend class base::RefCounted<ServiceWorkerVersion>;
   friend class ServiceWorkerMetrics;
@@ -455,6 +461,7 @@ class CONTENT_EXPORT ServiceWorkerVersion
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerActivationTest, SkipWaiting);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerActivationTest,
                            SkipWaitingWithInflightRequest);
+  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerVersionBrowserTest, MessageSelf);
 
   class Metrics;
   class PingController;
@@ -588,6 +595,8 @@ class CONTENT_EXPORT ServiceWorkerVersion
   static const int kRequestTimeoutMinutes;
   // Timeout for the worker to stop.
   static const int kStopWorkerTimeoutSeconds;
+  // Time to wait until stopping an idle worker.
+  static const int kIdleWorkerTimeoutSeconds;
 
   ~ServiceWorkerVersion() override;
 
@@ -795,6 +804,8 @@ class CONTENT_EXPORT ServiceWorkerVersion
   // long.
   base::TimeTicks stale_time_;
 
+  base::TimeTicks max_request_expiration_time_;

[falken, 2016/11/21 08:01:48]

nit: All these times are hard to keep track off so I'd prefer a comment like
"the expiration time of the request with the latest expiration time".

[Marijn Kruisselbrink, 2016/12/01 19:54:30]

Done

+
   // Keeps track of requests for timeout purposes. Requests are sorted by
   // their expiration time (soonest to expire on top of the priority queue). The
   // timeout timer periodically checks |timeout_queue_| for entries that should