BackgroundSyncManager tracks client registrations

content/browser/background_sync/client_background_sync_registration.h

+// Copyright 2015 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_SYNC_CLIENT_BACKGROUND_SYNC_REGISTRATION_H_
+#define CONTENT_BROWSER_BACKGROUND_SYNC_CLIENT_BACKGROUND_SYNC_REGISTRATION_H_
+
+#include "base/callback.h"
+#include "content/browser/background_sync/background_sync_registration.h"
+#include "content/browser/background_sync/background_sync_status.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class BackgroundSyncManager;
+
+// BackgroundSyncRegistrations that are exposed to clients. They call
+// ReleaseRegistration on deletion and provide access to Unregister.
+// ClientBackgroundSyncRegistration objects must be deleted before the
+// BackgroundSyncManager is deleted.
+class CONTENT_EXPORT ClientBackgroundSyncRegistration
+    : public BackgroundSyncRegistration {
+ public:
+  using StatusCallback = base::Callback<void(BackgroundSyncStatus)>;
+
+  explicit ClientBackgroundSyncRegistration(
+      BackgroundSyncManager* background_sync_manager);
+  ~ClientBackgroundSyncRegistration() override;
+
+  // Unregisters the background sync registration.  Calls |callback|
+  // with BACKGROUND_SYNC_STATUS_OK on success.

[iclelland, 2015/08/17 19:22:02]

And never, ever fails ;)

(I don't know if we need to specify what happens on failure, but it feels wrong
that we're missing any mention of it)

[jkarlin, 2015/08/18 15:12:38]

:) Changed to "if it succeeds". 

+  void Unregister(int64 service_worker_id, const StatusCallback& callback);
+
+  bool IsValid() const override;
+
+ private:
+  // This object must be deleted before the BackgroundSyncManager
+  // is deleted.
+  BackgroundSyncManager* background_sync_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(ClientBackgroundSyncRegistration);
+};
+
+}  // namespace
+
+#endif  // CONTENT_BROWSER_BACKGROUND_SYNC_CLIENT_BACKGROUND_SYNC_REGISTRATION_H_