Fix chart-legend-test.instantiate_basic
Fix chart-legend-test.instantiate_basic

BUG=catapult:#1734

Review URL: https://codereview.chromium.org/1412103011

SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,catapult-project/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,sahiljain/catapult,sahiljain/catapult,benschmaus/catapult,catapult-project/catapult,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,SummerLW/Perf-Insight-Report,benschmaus/catapult,sahiljain/catapult,catapult-project/catapult-csm,benschmaus/catapult,sahiljain/catapult,catapult-project/catapult-csm,catapult-project/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult,catapult-project/catapult,benschmaus/catapult,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,catapult-project/catapult,benschmaus/catapult,sahiljain/catapult,sahiljain/catapult,benschmaus/catapult