These metrics are still based on single stream and multiple streams bandwidth, not the parallelizable data we collect recently.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a672d19ad76be908d9339fe093f88fd1e66b99f8

commit a672d19ad76be908d9339fe093f88fd1e66b99f8
Author: xingliu <xingliu@chromium.org>
Date: Sat May 13 22:04:18 2017

Add the metric to record  percentage improvement for parallel download.

Records the ratio of bandwidth of parallel streams to the bandwidth of
single stream, and the ratio of total time to download a file with
parallel streams bandwidth to the actual total time.

BUG= 720168 

Review-Url: https://codereview.chromium.org/2874603002
Cr-Commit-Position: refs/heads/master@{#471608}

[modify] https://crrev.com/a672d19ad76be908d9339fe093f88fd1e66b99f8/content/browser/download/download_stats.cc
[modify] https://crrev.com/a672d19ad76be908d9339fe093f88fd1e66b99f8/tools/metrics/histograms/histograms.xml

Your change meets the bar and is auto-approved for M59. Please go ahead and merge the CL to branch 3071 manually. Please contact milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), gkihumba@(ChromeOS), Abdul Syed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/91c41eb0feb9bcba37aebde247cc66f78bdc6f17

commit 91c41eb0feb9bcba37aebde247cc66f78bdc6f17
Author: Xing Liu <xingliu@chromium.org>
Date: Mon May 15 18:19:08 2017

Add the metric to record  percentage improvement for parallel download.

Records the ratio of bandwidth of parallel streams to the bandwidth of
single stream, and the ratio of total time to download a file with
parallel streams bandwidth to the actual total time.

BUG= 720168 

Review-Url: https://codereview.chromium.org/2874603002
Cr-Original-Commit-Position: refs/heads/master@{#471608}
Review-Url: https://codereview.chromium.org/2886523002 .
Cr-Commit-Position: refs/branch-heads/3071@{#558}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}

[modify] https://crrev.com/91c41eb0feb9bcba37aebde247cc66f78bdc6f17/content/browser/download/download_stats.cc
[modify] https://crrev.com/91c41eb0feb9bcba37aebde247cc66f78bdc6f17/tools/metrics/histograms/histograms.xml