Run yapf in presubmit script.

yapf is a Python code formatter like clang-format. It will
eliminate unproductive coding-style discussions.

CQ-DEPEND=CL:566345
BUG=chromium:733103
TEST=bin/run_yapf ci_results_archiver
TEST=bin/run_yapf -i ci_results_archiver

Change-Id: I3eb97d3d6617dd68f538c6df06efd832e6bc6b31
Reviewed-on: https://chromium-review.googlesource.com/566347
Commit-Ready: Shuhei Takahashi <nya@chromium.org>
Tested-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Shuhei Takahashi <nya@chromium.org>
4 files changed