Do not draw inactive tiles
Do not draw inactive tiles

TBR=vmpstr
BUG=591

Review URL: https://codereview.appspot.com/128470043
zeptonaut/catapult,vmpstr/trace-viewer,sahiljain/catapult,catapult-project/catapult,benschmaus/catapult,catapult-project/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,vmpstr/trace-viewer,modulexcite/catapult,benschmaus/catapult,sahiljain/catapult,catapult-project/catapult,catapult-project/catapult-csm,zeptonaut/catapult,dstockwell/catapult,benschmaus/catapult,0x90sled/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,vmpstr/trace-viewer,danbeam/catapult,catapult-project/catapult-csm,dstockwell/catapult,danbeam/catapult,scottmcmaster/catapult,benschmaus/catapult,sahiljain/catapult,0x90sled/catapult,benschmaus/catapult,sahiljain/catapult,modulexcite/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,scottmcmaster/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,zeptonaut/catapult,0x90sled/catapult,SummerLW/Perf-Insight-Report,scottmcmaster/catapult,dstockwell/catapult,catapult-project/catapult,danbeam/catapult,sahiljain/catapult,sahiljain/catapult,danbeam/catapult,dstockwell/catapult,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,modulexcite/catapult