Update installed ServiceWorkers.

content/browser/service_worker/service_worker_version.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/service_worker/service_worker_version.h"
 
 #include "base/command_line.h"
 #include "base/stl_util.h"
 #include "base/strings/string16.h"
 #include "content/browser/service_worker/embedded_worker_instance.h"
@@ skipping 198 matching lines @@
                  weak_factory_.GetWeakPtr()));
 }
 
 void ServiceWorkerVersion::DeferScheduledUpdate() {
   if (update_timer_.IsRunning())
     update_timer_.Reset();
 }
 
 void ServiceWorkerVersion::StartUpdate() {
   update_timer_.Stop();
-  // TODO(michaeln): write me
+  if (!context_)
+    return;
+  ServiceWorkerRegistration* registration =
+      context_->GetLiveRegistration(registration_id_);
+  if (!registration)
+    return;
+  context_->UpdateServiceWorker(registration);
 }
 
 void ServiceWorkerVersion::SendMessage(
     const IPC::Message& message, const StatusCallback& callback) {
   if (running_status() != RUNNING) {
     // Schedule calling this method after starting the worker.
     StartWorker(base::Bind(&RunTaskAfterStartWorker,
                            weak_factory_.GetWeakPtr(), callback,
                            base::Bind(&self::SendMessage,
                                       weak_factory_.GetWeakPtr(),
@@ skipping 420 matching lines @@
     return;
   }
   stop_worker_timer_.Start(
       FROM_HERE, base::TimeDelta::FromSeconds(kStopWorkerDelay),
       base::Bind(&ServiceWorkerVersion::StopWorker,
                  weak_factory_.GetWeakPtr(),
                  base::Bind(&ServiceWorkerUtils::NoOpStatusCallback)));
 }
 
 }  // namespace content