Furthermore avoid lock-step between pointer updating phases as they
should execute in parallel without synchronization restrictions.

This reverts commit bc6adb86.

Bug: chromium:726040
Change-Id: I1713d4333f0ce1604ff51c02461f3ef91e4bdaed
Reviewed-on: https://chromium-review.googlesource.com/521062Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45657}