[Background Fetch] Tidy up getting/activating pending requests

content/browser/background_fetch/background_fetch_data_manager.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_DATA_MANAGER_H_
 #define CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_DATA_MANAGER_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 15 matching lines @@
 class BlobHandle;
 class BrowserContext;
 class ChromeBlobStorageContext;
 
 // The BackgroundFetchDataManager keeps track of all of the outstanding requests
 // which are in process in the DownloadManager. When Chromium restarts, it is
 // responsibile for reconnecting all the in progress downloads with an observer
 // which will keep the metadata up to date.
 class CONTENT_EXPORT BackgroundFetchDataManager {
  public:
-  using CreateRegistrationCallback = base::OnceCallback<void(
-      blink::mojom::BackgroundFetchError,
-      std::vector<scoped_refptr<BackgroundFetchRequestInfo>>)>;
+  using CreateRegistrationCallback =
+      base::OnceCallback<void(blink::mojom::BackgroundFetchError)>;
   using DeleteRegistrationCallback =
       base::OnceCallback<void(blink::mojom::BackgroundFetchError)>;
   using NextRequestCallback =
       base::OnceCallback<void(scoped_refptr<BackgroundFetchRequestInfo>)>;
+  using MarkedCompleteCallback =
+      base::OnceCallback<void(bool /* has_pending_or_active_requests */)>;
   using SettledFetchesCallback =
       base::OnceCallback<void(blink::mojom::BackgroundFetchError,
                               bool /* background_fetch_succeeded */,
                               std::vector<BackgroundFetchSettledFetch>,
                               std::vector<std::unique_ptr<BlobHandle>>)>;
 
   explicit BackgroundFetchDataManager(BrowserContext* browser_context);
   ~BackgroundFetchDataManager();
 
   // Creates and stores a new registration with the given properties. Will
   // invoke the |callback| when the registration has been created, which may
   // fail due to invalid input or storage errors.
   void CreateRegistration(
       const BackgroundFetchRegistrationId& registration_id,
       const std::vector<ServiceWorkerFetchRequest>& requests,
       const BackgroundFetchOptions& options,
       CreateRegistrationCallback callback);
 
+  // Activates the next pending request, if any, such that it is ready to be
+  // started, and invokes the |callback| with that request, else a null request.

[Peter Beverloo, 2017/07/12 13:30:50]

nit: update comment ("activate")

[johnme, 2017/07/12 14:13:57]

Done.

+  void PopNextRequest(const BackgroundFetchRegistrationId& registration_id,
+                      NextRequestCallback callback);
+
   // Marks that the |request|, part of the Background Fetch identified by
   // |registration_id|, has been started as |download_guid|.
   void MarkRequestAsStarted(
       const BackgroundFetchRegistrationId& registration_id,
       BackgroundFetchRequestInfo* request,
       const std::string& download_guid);
 
   // Marks that the |request|, part of the Background Fetch identified by
-  // |registration_id|, has completed. Will invoke the |callback| with the
-  // next request, if any, when the operation has completed.
-  void MarkRequestAsCompleteAndGetNextRequest(
+  // |registration_id|, has completed.
+  void MarkRequestAsComplete(
       const BackgroundFetchRegistrationId& registration_id,
       BackgroundFetchRequestInfo* request,
-      NextRequestCallback callback);
+      MarkedCompleteCallback callback);
 
   // Reads all settled fetches for the given |registration_id|. Both the Request
   // and Response objects will be initialised based on the stored data. Will
   // invoke the |callback| when the list of fetches has been compiled.
   void GetSettledFetchesForRegistration(
       const BackgroundFetchRegistrationId& registration_id,
       SettledFetchesCallback callback);
 
   // Deletes the registration identified by |registration_id|. Will invoke the
   // |callback| when the registration has been deleted from storage.
@@ skipping 15 matching lines @@
   SEQUENCE_CHECKER(sequence_checker_);
 
   base::WeakPtrFactory<BackgroundFetchDataManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundFetchDataManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_DATA_MANAGER_H_