Read and restore persisted slice info

components/history/content/browser/download_database_helper.cc

+// 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.
+
+#include "components/history/content/browser/download_database_helper.h"
+
+namespace history {
+
+std::vector<content::DownloadItem::ReceivedSlice> ToContentReceivedSlices(
+    const std::vector<DownloadSliceInfo>& info) {
+  std::vector<content::DownloadItem::ReceivedSlice> result;
+  for (const auto& slice_info : info) {
+    result.push_back(content::DownloadItem::ReceivedSlice(
+        slice_info.offset, slice_info.received_bytes));
+  }
+  return result;
+}
+
+}  // namespace history