Add support for OfflinePagesDownloadBridge.

components/offline_pages/downloads/download_ui_item.cc

+// 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.
+
+#include "components/offline_pages/downloads/download_ui_item.h"
+
+namespace offline_pages {
+
+DownloadUIItem::DownloadUIItem()
+    : total_bytes(0) {
+}
+
+DownloadUIItem::DownloadUIItem(const OfflinePageItem& page)
+    : guid(page.client_id.id),
+      url(page.url),
+      target_path(page.file_path),
+      start_time(page.creation_time),
+      total_bytes(page.file_size) {}
+
+DownloadUIItem::~DownloadUIItem() {
+}
+
+}  // namespace offline_pages