This is a reland of 5fd1defb
Original change's description:
> gclient runhooks: now with less spammy progress notifications
> 
> Bug: 772741
> Change-Id: I62ad64219ba27ee4ea26ceb603b1133dff4a2e04
> Reviewed-on: https://chromium-review.googlesource.com/727194
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Reviewed-by: Dirk Pranke <dpranke@chromium.org>
> Commit-Queue: Daniel Cheng <dcheng@chromium.org>

Bug: 772741
Change-Id: Idd6fcd46a8c97716d68ed0975940705a90540a4d
Reviewed-on: https://chromium-review.googlesource.com/728961Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>