Forces the chart to check its dimensions when a new picture is set
Forces the chart to check its dimensions when a new picture is set

TBR=dsinclair

Review URL: https://codereview.appspot.com/13277045
dstockwell/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,sahiljain/catapult,dstockwell/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult-csm,benschmaus/catapult,danbeam/catapult,vmpstr/trace-viewer,zeptonaut/catapult,catapult-project/catapult,sahiljain/catapult,dstockwell/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,0x90sled/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,benschmaus/catapult,modulexcite/catapult,SummerLW/Perf-Insight-Report,SummerLW/Perf-Insight-Report,modulexcite/catapult,scottmcmaster/catapult,catapult-project/catapult,dstockwell/catapult,danbeam/catapult,modulexcite/catapult,sahiljain/catapult,sahiljain/catapult,catapult-project/catapult,vmpstr/trace-viewer,0x90sled/catapult,sahiljain/catapult,catapult-project/catapult,0x90sled/catapult,sahiljain/catapult,danbeam/catapult,catapult-project/catapult,catapult-project/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,danbeam/catapult,zeptonaut/catapult,benschmaus/catapult,vmpstr/trace-viewer,catapult-project/catapult-csm,scottmcmaster/catapult,benschmaus/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,zeptonaut/catapult,catapult-project/catapult-csm,scottmcmaster/catapult