[task scheduler] Add FuncTimers
[task scheduler] Add FuncTimers

BUG=skia:

Change-Id: If3728cec5c9993ea62893de12f267029b33a0c9a
Reviewed-on: https://skia-review.googlesource.com/4883
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>
Reviewed-by: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot