[Offline pages] Downloads UI: Adding bridge for issuing notifications

components/offline_pages/downloads/offline_page_download_notifier.h

+// Copyright 2016 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 COMPONENTS_OFFLINE_PAGES_DOWNLOADS_OFFLINE_PAGE_DOWNLOAD_NOTIFIER_H_
+#define COMPONENTS_OFFLINE_PAGES_DOWNLOADS_OFFLINE_PAGE_DOWNLOAD_NOTIFIER_H_
+
+#include "components/offline_pages/downloads/download_ui_item.h"
+
+namespace offline_pages {
+
+struct OfflinePageDownloadNotifier {
+ public:
+  virtual ~OfflinePageDownloadNotifier() = default;
+
+  virtual void NotifyDownloadSuccessful(const DownloadUIItem& item) = 0;
+  virtual void NotifyDownloadFailed(const DownloadUIItem& item) = 0;
+  virtual void NotifyDownloadProgress(const DownloadUIItem& item) = 0;
+  virtual void NotifyDownloadPaused(const DownloadUIItem& item) = 0;
+  virtual void NotifyDownloadInterrupted(const DownloadUIItem& item) = 0;
+  virtual void NotifyDownloadCanceled(const DownloadUIItem& item) = 0;
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_DOWNLOADS_OFFLINE_PAGE_DOWNLOAD_NOTIFIER_H_