GitLab

Allow a session to specify a request ID. Normally if
a session abandons focus and then requests it again
we would give it a new ID. This preserves the ID
to avoid making the UI flash.

BUG=988106

Change-Id: Iecf95bad2276908bb1d5910d3aebd17c25731f0d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1721039Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Tommy Steimel <steimel@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684161}