This patch also fixes several cctests that require manual GC.

BUG=chromium:694255

Change-Id: Ida93ed2498a6c5b0187ee78d2b1da27d2ff1906a
Reviewed-on: https://chromium-review.googlesource.com/533233
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45913}