This is a move-only CL (except includes cleanup).

Bug: v8:6666
Change-Id: I28422b4a21074e642e8d5c9b3a563ecafdafbda7
Reviewed-on: https://chromium-review.googlesource.com/957087Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51838}