Introduce ServiceWorkerHandle for tracking WebServiceWorkerImpl reference

content/browser/service_worker/service_worker_browsertest.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 "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/run_loop.h"
 #include "content/browser/service_worker/embedded_worker_instance.h"
 #include "content/browser/service_worker/embedded_worker_registry.h"
@@ skipping 205 matching lines @@
 };
 
 class ServiceWorkerVersionBrowserTest : public ServiceWorkerBrowserTest {
  public:
   typedef ServiceWorkerVersionBrowserTest self;
 
   ServiceWorkerVersionBrowserTest() : next_registration_id_(1) {}
   virtual ~ServiceWorkerVersionBrowserTest() {}
 
   virtual void TearDownOnIOThread() OVERRIDE {
-    if (registration_) {
-      registration_->Shutdown();
-      registration_ = NULL;
-    }
-    if (version_) {
-      version_->Shutdown();
-      version_ = NULL;
-    }
+    registration_ = NULL;
+    version_ = NULL;
   }
 
   void InstallTestHelper(const std::string& worker_url,
                          ServiceWorkerStatusCode expected_status) {
     RunOnIOThread(base::Bind(&self::SetUpRegistrationOnIOThread, this,
                              worker_url));
 
     // Dispatch install on a worker.
     ServiceWorkerStatusCode status = SERVICE_WORKER_ERROR_FAILED;
     base::RunLoop install_run_loop;
@@ skipping 349 matching lines @@
         base::Bind(&ServiceWorkerBlackBoxBrowserTest::FindRegistrationOnIO,
                    this,
                    embedded_test_server()->GetURL("/service_worker/empty.html"),
                    &status,
                    &script_url));
     EXPECT_EQ(SERVICE_WORKER_ERROR_NOT_FOUND, status);
   }
 }
 
 }  // namespace content