The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/462abbbe5b9206198afacbb76f5286da80de1106

commit 462abbbe5b9206198afacbb76f5286da80de1106
Author: qinmin <qinmin@chromium.org>
Date: Wed May 03 21:55:42 2017

Fix the Unthrottled download count for parallel download

Only the main request should report a count, not the parallel requests.

BUG= 717679 

Review-Url: https://codereview.chromium.org/2854973003
Cr-Commit-Position: refs/heads/master@{#469147}

[modify] https://crrev.com/462abbbe5b9206198afacbb76f5286da80de1106/content/browser/download/download_manager_impl.cc
[modify] https://crrev.com/462abbbe5b9206198afacbb76f5286da80de1106/content/browser/download/download_request_core.cc
[modify] https://crrev.com/462abbbe5b9206198afacbb76f5286da80de1106/content/browser/download/download_request_core.h
[modify] https://crrev.com/462abbbe5b9206198afacbb76f5286da80de1106/content/browser/download/download_resource_handler.cc
[modify] https://crrev.com/462abbbe5b9206198afacbb76f5286da80de1106/content/browser/download/download_worker.cc
[modify] https://crrev.com/462abbbe5b9206198afacbb76f5286da80de1106/content/browser/download/url_downloader.cc
[modify] https://crrev.com/462abbbe5b9206198afacbb76f5286da80de1106/content/browser/download/url_downloader.h