[Cronet] Add info and status to correlate UrlRequestInfo to requests.

Bug: 879208
Change-Id: Ic76e31d1430e6800b1302c3cfb7a8baa76b4643f
Reviewed-on: https://chromium-review.googlesource.com/c/1399054
Commit-Queue: Caleb Raitto <caraitto@chromium.org>
Reviewed-by: Paul Jensen <pauljensen@chromium.org>
Reviewed-by: Misha Efimov <mef@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623378}