Hook up BackgroundFetchServiceImpl::Fetch() to start a fetch

content/browser/background_fetch/background_fetch_test_base.h

 // Copyright 2017 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.
 
 #ifndef CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_TEST_BASE_H_
 #define CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_TEST_BASE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 14 matching lines @@
 // the Background Fetch feature.
 class BackgroundFetchTestBase : public ::testing::Test {
  public:
   BackgroundFetchTestBase();
   ~BackgroundFetchTestBase() override;
 
   // ::testing::Test overrides.
   void SetUp() override;
   void TearDown() override;
 
-  // Creates a valid Service Worker registration for the testing origin and
-  // stores the data in the |*registration_id|. Returns whether creation was
-  // successful, which must be asserted by tests.
+  // Creates a Background Fetch registration backed by a Service Worker
+  // registration for the testing origin. The resulting registration will be
+  // stored in |*registration_id|. Returns whether creation was successful,
+  // which must be asserted by tests. The ServiceWorkerRegistration that
+  // backs the |*registration_id| will be kept alive for the test's lifetime.
   bool CreateRegistrationId(const std::string& tag,
                             BackgroundFetchRegistrationId* registration_id)
       WARN_UNUSED_RESULT;
 
   // Returns the embedded worker test helper instance, which can be used to
   // influence the behaviour of the Service Worker events.
   BackgroundFetchEmbeddedWorkerTestHelper* embedded_worker_test_helper() {
     return &embedded_worker_test_helper_;
   }
 
@@ skipping 14 matching lines @@
 
   bool set_up_called_ = false;
   bool tear_down_called_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundFetchTestBase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_TEST_BASE_H_