Add new UMA stats for parallelizable download

content/browser/download/download_browsertest.cc

 // Copyright (c) 2012 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.
 
 // This file contains download browser tests that are known to be runnable
 // in a pure content context.  Over time tests should be migrated here.
 
 #include <stddef.h>
 #include <stdint.h>
 #include <utility>
@@ skipping 306 matching lines @@
                          observer) {}
 
   ~CountingDownloadFile() override {
     DCHECK_CURRENTLY_ON(BrowserThread::FILE);
     active_files_--;
   }
 
   void Initialize(
       const InitializeCallback& callback,
       const CancelRequestCallback& cancel_request_callback,
-      const DownloadItem::ReceivedSlices& received_slices) override {
+      const DownloadItem::ReceivedSlices& received_slices,
+      bool is_parallelizable) override {
     DCHECK_CURRENTLY_ON(BrowserThread::FILE);
     active_files_++;
     DownloadFileImpl::Initialize(callback, cancel_request_callback,
-                                 received_slices);
+                                 received_slices, is_parallelizable);
   }
 
   static void GetNumberActiveFiles(int* result) {
     DCHECK_CURRENTLY_ON(BrowserThread::FILE);
     *result = active_files_;
   }
 
   // Can be called on any thread, and will block (running message loop)
   // until data is returned.
   static int GetNumberActiveFilesFromFileThread() {
@@ skipping 2306 matching lines @@
   GURL document_url =
       origin_two.GetURL("/iframe-host.html?target=" + frame_url.spec());
   DownloadItem* download = StartDownloadAndReturnItem(shell(), document_url);
   WaitForCompletion(download);
 
   EXPECT_STREQ(FILE_PATH_LITERAL("download-test.lib"),
                download->GetTargetFilePath().BaseName().value().c_str());
 }
 
 }  // namespace content