ServiceWorker: Add prepare_callback in DispatchFetchEvent to notify the end of SW preparation.

content/browser/service_worker/service_worker_fetch_dispatcher.cc

 // Copyright 2014 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_fetch_dispatcher.h"
 
 #include "base/bind.h"
 #include "content/browser/service_worker/service_worker_version.h"
 
 namespace content {
 
 ServiceWorkerFetchDispatcher::ServiceWorkerFetchDispatcher(
     scoped_ptr<ServiceWorkerFetchRequest> request,
     ServiceWorkerVersion* version,
-    const FetchCallback& callback)
+    const base::Closure& prepare_callback,
+    const FetchCallback& fetch_callback)
     : version_(version),
-      callback_(callback),
+      prepare_callback_(prepare_callback),
+      fetch_callback_(fetch_callback),
       request_(request.Pass()),
       weak_factory_(this) {
 }
 
 ServiceWorkerFetchDispatcher::~ServiceWorkerFetchDispatcher() {}
 
 void ServiceWorkerFetchDispatcher::Run() {
   DCHECK(version_->status() == ServiceWorkerVersion::ACTIVATING ||
          version_->status() == ServiceWorkerVersion::ACTIVATED)
       << version_->status();
@@ skipping 22 matching lines @@
   // to the associated documents and association must be dropped
   // at this point)
   DidFinish(SERVICE_WORKER_ERROR_ACTIVATE_WORKER_FAILED,
             SERVICE_WORKER_FETCH_EVENT_RESULT_FALLBACK,
             ServiceWorkerResponse());
 }
 
 void ServiceWorkerFetchDispatcher::DispatchFetchEvent() {
   version_->DispatchFetchEvent(
       *request_.get(),
+      base::Bind(&ServiceWorkerFetchDispatcher::DidPrepare,
+                 weak_factory_.GetWeakPtr()),
       base::Bind(&ServiceWorkerFetchDispatcher::DidFinish,
                  weak_factory_.GetWeakPtr()));
 }
 
+void ServiceWorkerFetchDispatcher::DidPrepare() {
+  DCHECK(!prepare_callback_.is_null());
+  base::Closure prepare_callback = prepare_callback_;
+  prepare_callback.Run();
+}
+
 void ServiceWorkerFetchDispatcher::DidFinish(
     ServiceWorkerStatusCode status,
     ServiceWorkerFetchEventResult fetch_result,
     const ServiceWorkerResponse& response) {
-  DCHECK(!callback_.is_null());
-  FetchCallback callback = callback_;
-  callback.Run(status, fetch_result, response);
+  DCHECK(!fetch_callback_.is_null());
+  FetchCallback fetch_callback = fetch_callback_;
+  fetch_callback.Run(status, fetch_result, response);
 }
 
 }  // namespace content