The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8176fd9dfe1fc66c03052aeb8fc935fb095729b0

commit 8176fd9dfe1fc66c03052aeb8fc935fb095729b0
Author: Min Qin <qinmin@chromium.org>
Date: Mon Nov 20 18:21:06 2017

Network Service: Set the initiator before starting URLRequest

The initiator is used for checking cookies.
And it is mising from the URLRequest when URLLoader is used.
For example, DownloadContentTest.DownloadAttributeSameOriginRedirect will redirect
a link click to a download with a different origin.
Download should pass the initiator in the URLRequest,
but missing it causes the wrong cookie to be passed.
This CL sets the intiator in the URLRequest so the above test can partially work.

BUG= 786598 

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I4efffd41fc9ca26063d853ce03e7c7ff817a917c
Reviewed-on: https://chromium-review.googlesource.com/777552
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517864}
[modify] https://crrev.com/8176fd9dfe1fc66c03052aeb8fc935fb095729b0/content/network/url_loader.cc