crosperf: fix lint warnings.

BUG=chromium:570454
TEST=unittest passes, lint warning is gone.

Change-Id: I230e9de9c1912f05774444d15310ad70e07e264b
Reviewed-on: https://chrome-internal-review.googlesource.com/243215
Commit-Ready: Yunlian Jiang <yunlian@google.com>
Tested-by: Yunlian Jiang <yunlian@google.com>
Reviewed-by: Yunlian Jiang <yunlian@google.com>
2 files changed