Don't drop messages/events send to a service worker that is stopping.

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 1e00b8227637cf7c82500244f7145911610324ca..693b10d3171c13b5fdf1edbc8fc3ad20a828c4d5 100644
--- a/content/browser/service_worker/service_worker_version.cc
+++ b/content/browser/service_worker/service_worker_version.cc
@@ -177,13 +177,15 @@ void ServiceWorkerVersion::StartWorker(const StatusCallback& callback) {
 void ServiceWorkerVersion::StartWorker(
     bool pause_after_download,
     const StatusCallback& callback) {
+  if (is_doomed()) {
+    RunSoon(base::Bind(callback, SERVICE_WORKER_ERROR_START_WORKER_FAILED));
+    return;
+  }
   switch (running_status()) {
     case RUNNING:
       RunSoon(base::Bind(callback, SERVICE_WORKER_OK));
       return;
     case STOPPING:
-      RunSoon(base::Bind(callback, SERVICE_WORKER_ERROR_START_WORKER_FAILED));
-      return;
     case STOPPED:
     case STARTING:
       start_callbacks_.push_back(callback);
@@ -543,16 +545,22 @@ void ServiceWorkerVersion::OnStarted() {
   FOR_EACH_OBSERVER(Listener, listeners_, OnWorkerStarted(this));
 }
 
-void ServiceWorkerVersion::OnStopped() {
+void ServiceWorkerVersion::OnStopped(
+    EmbeddedWorkerInstance::Status old_status) {
   DCHECK_EQ(STOPPED, running_status());
   scoped_refptr<ServiceWorkerVersion> protect(this);
 
+  bool should_restart = !is_doomed() && !start_callbacks_.empty() &&
+                        (old_status != EmbeddedWorkerInstance::STARTING);
+
   // Fire all stop callbacks.
   RunCallbacks(this, &stop_callbacks_, SERVICE_WORKER_OK);
 
-  // Let all start callbacks fail.
-  RunCallbacks(
-      this, &start_callbacks_, SERVICE_WORKER_ERROR_START_WORKER_FAILED);
+  if (!should_restart) {
+    // Let all start callbacks fail.
+    RunCallbacks(this, &start_callbacks_,
+                 SERVICE_WORKER_ERROR_START_WORKER_FAILED);
+  }
 
   // Let all message callbacks fail (this will also fire and clear all
   // callbacks for events).
@@ -584,6 +592,15 @@ void ServiceWorkerVersion::OnStopped() {
   // the listener prevents any pending completion callbacks from causing
   // messages to be sent to the stopped worker.
   cache_listener_.reset();
+
+  // Restart worker if we have any start callbacks and the worker isn't doomed.
+  if (should_restart) {
+    cache_listener_.reset(new ServiceWorkerCacheListener(this, context_));
+    embedded_worker_->Start(
+        version_id_, scope_, script_url_, false /* pause_after_download */,
+        base::Bind(&ServiceWorkerVersion::OnStartMessageSent,
+                   weak_factory_.GetWeakPtr()));
+  }
 }
 
 void ServiceWorkerVersion::OnReportException(