add a few OWNERS files below tools/

BUG=none

Review URL: https://codereview.chromium.org/1433043002

Cr-Original-Commit-Position: refs/heads/master@{#358909}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: f841024ad8594dfcdffb9a5285920d0ceeff84fc
1 file changed