Completely remove base_dir
Completely remove base_dir

According to https://codereview.chromium.org/1781663006/

Review URL: https://codereview.chromium.org/1787153002

benschmaus/catapult,sahiljain/catapult,benschmaus/catapult,catapult-project/catapult,catapult-project/catapult,benschmaus/catapult,benschmaus/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult-csm,sahiljain/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,sahiljain/catapult,benschmaus/catapult,catapult-project/catapult,benschmaus/catapult,sahiljain/catapult,sahiljain/catapult,catapult-project/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult-csm,sahiljain/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,catapult-project/catapult