Generate TaskScheduler::InitParams from components/task_scheduler_util/.

Initialization of TaskScheduler with a vector of
SchedulerWorkerPoolParams is being deprecated in favor of
initialization with a TaskScheduler::InitParams struct that contains
a fixed number of SchedulerWorkerPoolParams members.

BUG=690706

Review-Url: https://codereview.chromium.org/2788223002
Cr-Commit-Position: refs/heads/master@{#461698}
8 files changed