Use TaskScheduler instead of SequencedWorkerPool in ios_component_updater_configurator.cc.

SequencedWorkerPool is being deprecated in favor of TaskScheduler.

BUG=667892
R=droger@chromium.org

Review-Url: https://codereview.chromium.org/2875423002
Cr-Commit-Position: refs/heads/master@{#473883}
1 file changed