Change android's device file format to a json list.
Change android's device file format to a json list.

BUG=chromium:612360

Review-Url: https://codereview.chromium.org/2046593004

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