Add UMA metric to track parallel download requests stats.

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 203 matching lines @@
 
 // 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);
 
 // Increment one of the count for parallel download.
 void RecordParallelDownloadCount(DownloadCountTypes type);
 
+// Records the actual total number of requests sent for a parallel download,
+// including the initial request.
+void RecordParallelDownloadRequestCount(int request_count);
+
+// Records the number of requests that have smaller offset than the initial
+// request.
+void RecordParallelDownloadEarlyRequests(int request_count);
+
+// Record if each byte stream is successfully added to download sink.
+void RecordParallelDownloadAddStreamSuccess(bool success);
+
 // 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(
@@ skipping 36 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_