GitLab

- Extract common set up for incoming connections
- Extract common set up for accept / reject flows
- Add a TODO for fetching certificate for outgoing share target based on parent CL

Bug: 1085068
Change-Id: I3b3e322026c3cfe2fe86808f92bfd0b1d810f94b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2344604
Commit-Queue: Himanshu Jaju <himanshujaju@chromium.org>
Reviewed-by: Richard Knoll <knollr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796503}