service worker: Don't crash when selecting Offline mode in DevTools.

When ServiceWorkerOnUI is enabled, methods must be called on the UI
thread.

This adds a test that would crash when run_web_tests.py is run with
--additional-driver-flag="--enable-features=ServiceWorkerOnUI" before
the fix.

Bug: 1030543
Change-Id: Ibdd7cbac3fd92900dc78d538237f5f8b1a3a96f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1980252Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727144}

content/browser/devtools/protocol/network_handler.cc

@@ -751,27 +751,28 @@ class BackgroundSyncRestorer {
         static_cast<StoragePartitionImpl*>(storage_partition_)
             ->GetBackgroundSyncContext();
     if (offline) {
-      base::PostTask(
-          FROM_HERE, {BrowserThread::IO},
+      RunOrPostTaskOnThread(
+          FROM_HERE, ServiceWorkerContext::GetCoreThreadId(),
           base::BindOnce(
-              &SetServiceWorkerOfflineOnIO, sync_context,
-              base::RetainedRef(static_cast<ServiceWorkerContextWrapper*>(
+              &SetServiceWorkerOfflineOnServiceWorkerCoreThread, sync_context,
+              base::WrapRefCounted(static_cast<ServiceWorkerContextWrapper*>(
                   storage_partition_->GetServiceWorkerContext())),
               service_worker_host->version_id(),
               offline_sw_registration_id_.get()));
     } else {
-      base::PostTask(FROM_HERE, {BrowserThread::IO},
-                     base::BindOnce(&SetServiceWorkerOnlineOnIO, sync_context,
-                                    offline_sw_registration_id_.get()));
+      RunOrPostTaskOnThread(
+          FROM_HERE, ServiceWorkerContext::GetCoreThreadId(),
+          base::BindOnce(&SetServiceWorkerOnlineOnServiceWorkerCoreThread,
+                         sync_context, offline_sw_registration_id_.get()));
     }
   }
 
-  static void SetServiceWorkerOfflineOnIO(
+  static void SetServiceWorkerOfflineOnServiceWorkerCoreThread(
       scoped_refptr<BackgroundSyncContextImpl> sync_context,
       scoped_refptr<ServiceWorkerContextWrapper> swcontext,
       int64_t version_id,
       int64_t* offline_sw_registration_id) {
-    DCHECK_CURRENTLY_ON(BrowserThread::IO);
+    DCHECK_CURRENTLY_ON(ServiceWorkerContext::GetCoreThreadId());
     ServiceWorkerVersion* version = swcontext.get()->GetLiveVersion(version_id);
     if (!version)
       return;
@@ -783,10 +784,10 @@ class BackgroundSyncRestorer {
         registration_id, true);
   }
 
-  static void SetServiceWorkerOnlineOnIO(
+  static void SetServiceWorkerOnlineOnServiceWorkerCoreThread(
       scoped_refptr<BackgroundSyncContextImpl> sync_context,
       int64_t* offline_sw_registration_id) {
-    DCHECK_CURRENTLY_ON(BrowserThread::IO);
+    DCHECK_CURRENTLY_ON(ServiceWorkerContext::GetCoreThreadId());
     if (*offline_sw_registration_id ==
         blink::mojom::kInvalidServiceWorkerRegistrationId) {
       return;

third_party/blink/web_tests/http/tests/devtools/service-workers/offline-expected.txt

+Tests "Offline" checkbox does not crash. crbug.com/746220
+
+

third_party/blink/web_tests/http/tests/devtools/service-workers/offline.js

+// Copyright 2019 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.
+
+(async function() {
+  TestRunner.addResult(`Tests "Offline" checkbox does not crash. crbug.com/746220\n`);
+  await TestRunner.loadModule('application_test_runner');
+  // Note: every test that uses a storage API must manually clean-up state from previous tests.
+  await ApplicationTestRunner.resetState();
+
+  const scriptURL = 'resources/service-worker-empty.js';
+  const scope = 'resources/offline';
+
+  // Register a service worker.
+  await ApplicationTestRunner.registerServiceWorker(scriptURL, scope);
+  await ApplicationTestRunner.waitForActivated(scope);
+
+  // Switch offline mode on.
+  const oldNetwork = SDK.multitargetNetworkManager.networkConditions();
+  SDK.multitargetNetworkManager.setNetworkConditions(SDK.NetworkManager.OfflineConditions);
+
+  // Switch offline mode off.
+  SDK.multitargetNetworkManager.setNetworkConditions(oldNetwork);
+
+  // The test passes if it doesn't crash.
+  TestRunner.completeTest();
+})();