ServiceWorker: Update the install sequence as per the latest spec

content/child/service_worker/web_service_worker_impl.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/child/service_worker/web_service_worker_impl.h"
 
 #include "content/child/service_worker/service_worker_dispatcher.h"
 #include "content/child/service_worker/service_worker_handle_reference.h"
 #include "content/child/thread_safe_sender.h"
 #include "content/child/webmessageportchannel_impl.h"
@@ skipping 25 matching lines @@
   if (handle_ref_->handle_id() == kInvalidServiceWorkerHandleId)
     return;
   ServiceWorkerDispatcher* dispatcher =
       ServiceWorkerDispatcher::GetThreadSpecificInstance();
   if (dispatcher)
     dispatcher->RemoveServiceWorker(handle_ref_->handle_id());
 }
 
 void WebServiceWorkerImpl::OnStateChanged(
     blink::WebServiceWorkerState new_state) {
-  DCHECK(proxy_);
-  if (proxy_->isReady())
+  if (proxy_ && proxy_->isReady())
     CommitState(new_state);
   else
     queued_states_.push_back(new_state);
 }
 
 void WebServiceWorkerImpl::setProxy(blink::WebServiceWorkerProxy* proxy) {
   proxy_ = proxy;
 }
 
 blink::WebServiceWorkerProxy* WebServiceWorkerImpl::proxy() {
@@ skipping 33 matching lines @@
 }
 
 void WebServiceWorkerImpl::CommitState(blink::WebServiceWorkerState new_state) {
   DCHECK(proxy_);
   DCHECK(proxy_->isReady());
   state_ = new_state;
   proxy_->dispatchStateChangeEvent();
 }
 
 }  // namespace content