Removal of unneeded task_runner arg from Quirks init

Bug: 667892
Test: None (code refactor; no observable change)

This is a small cleanup resulting from crbug.com/667892#c352.  Unlike the
blocking_pool it replaced, creating the task_runner in Quirks code doesn't
cause a dependency violation, so no need to pass it as an init argument.

Change-Id: I3226a659ebbfa795e894a16b8ba9c55021fff118
Reviewed-on: https://chromium-review.googlesource.com/930026
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Greg Levin <glevin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538434}
4 files changed