[devil] Add support for line transformation to LogcatMonitor.
[devil] Add support for line transformation to LogcatMonitor.

Basically porting logdog_logcat_monitor's deobfuscate_func.

TBR=agrieve@chromium.org
Bug: chromium:772032
Change-Id: Ic57b38e522f93690d52eb090881b77c540aefb8f
Reviewed-on: https://chromium-review.googlesource.com/702922
Reviewed-by: John Budorick <17d38a2d68c6a07a3ab0ce4a2873c5acefbd3dbb@chromium.org>
Commit-Queue: John Budorick <17d38a2d68c6a07a3ab0ce4a2873c5acefbd3dbb@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult