Add UMA for estimating disk bandwidth and the time saved with parallel download

content/browser/download/download_stats.h

 // 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.
 //
 // Holds helpers for gathering UMA stats about downloads.
 
 #ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_
 
 #include <stddef.h>
@@ skipping 184 matching lines @@
 // was the bottleneck).
 void RecordNetworkBlockage(base::TimeDelta resource_handler_lifetime,
                            base::TimeDelta resource_handler_blocked_time);
 
 // Record overall bandwidth stats at the file end.
 // Does not count in any hash computation or file open/close time.
 void RecordFileBandwidth(size_t length,
                          base::TimeDelta disk_write_time,
                          base::TimeDelta elapsed_time);
 
+// Records the bandwidth for parallel download and estimates the saved time at
+// the file end. Does not count in any hash computation or file open/close time.
+void RecordParallelDownloadStats(
+    size_t bytes_downloaded_with_parallel_streams,
+    base::TimeDelta time_with_parallel_streams,
+    size_t bytes_downloaded_without_parallel_streams,
+    base::TimeDelta time_without_parallel_streams);
+
 // Record the result of a download file rename.
 void RecordDownloadFileRenameResultAfterRetry(
     base::TimeDelta time_since_first_failure,
     DownloadInterruptReason interrupt_reason);
 
 enum SavePackageEvent {
   // The user has started to save a page as a package.
   SAVE_PACKAGE_STARTED,
 
   // The save package operation was cancelled.
@@ skipping 28 matching lines @@
 
 void RecordDownloadConnectionSecurity(const GURL& download_url,
                                       const std::vector<GURL>& url_chain);
 
 void RecordDownloadSourcePageTransitionType(
     const base::Optional<ui::PageTransition>& transition);
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_