GitLab

Delete deprecated ScopedAllowWait and remove related friendship in
ThreadRestrictions.

Bug: 766678
Change-Id: I25c33b87150c6dbfb3325c4591d34919b975e59d
Reviewed-on: https://chromium-review.googlesource.com/c/1417790Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625440}