GitLab

As a result of the recent IO thread hopping removals,
|io_runner| is no longer needed.

Bug: 717812
Change-Id: I525785fda65a2edfaf86f11bcfcc21d6c74de85b
Reviewed-on: https://chromium-review.googlesource.com/1155830
Commit-Queue: Chase Phillips <cmp@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Chris Mumford <cmumford@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580331}