Introduce ParallelDownloadJob.

content/browser/download/mock_download_item_impl.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 "content/browser/download/mock_download_item_impl.h"
+
+namespace content {
+
+MockDownloadItemImpl::MockDownloadItemImpl(DownloadItemImplDelegate* delegate)
+    : DownloadItemImpl(delegate,
+                       std::string("7d122682-55b5-4a47-a253-36cadc3e5bee"),
+                       content::DownloadItem::kInvalidId,
+                       base::FilePath(),
+                       base::FilePath(),
+                       std::vector<GURL>(),
+                       GURL(),
+                       GURL(),
+                       GURL(),
+                       GURL(),
+                       "application/octet-stream",
+                       "application/octet-stream",
+                       base::Time(),
+                       base::Time(),
+                       std::string(),
+                       std::string(),
+                       0,
+                       0,
+                       std::string(),
+                       DownloadItem::COMPLETE,
+                       DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
+                       DOWNLOAD_INTERRUPT_REASON_NONE,
+                       false,
+                       std::vector<DownloadItem::ReceivedSlice>(),
+                       net::NetLogWithSource()) {}
+
+MockDownloadItemImpl::~MockDownloadItemImpl() = default;
+
+}  // namespace content