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

content/browser/service_worker/service_worker_version.cc

Index: content/browser/service_worker/service_worker_version.cc
diff --git a/content/browser/service_worker/service_worker_version.cc b/content/browser/service_worker/service_worker_version.cc
index 633822426aa67c3824d858e0d3626a7dc479f46f..498a9c3ba4af6f10b7bd1e644db14be1e02024d3 100644
--- a/content/browser/service_worker/service_worker_version.cc
+++ b/content/browser/service_worker/service_worker_version.cc
@@ -572,6 +572,8 @@ int ServiceWorkerVersion::StartRequestWithCustomTimeout(
   base::TimeTicks expiration_time = tick_clock_->NowTicks() + timeout;
   timeout_queue_.push(
       RequestInfo(request_id, event_type, expiration_time, timeout_behavior));
+  if (expiration_time > max_request_expiration_time_)
+    max_request_expiration_time_ = expiration_time;
   return request_id;
 }