Update tracing_project.IsThirdParty to include third_party in top level.
Update tracing_project.IsThirdParty to include third_party in top level.

This is needed to unblock https://codereview.appspot.com/251580043/ from being blocked by PRESUBMIT check.

*We have PRESUBMIT that scan all non third-party files for chromium
license. Since vinn has many huge binary files, that check makes
presubmit stalled.

R=nduca@google.com

Review URL: https://codereview.appspot.com/256290043 .

sahiljain/catapult,dstockwell/catapult,SummerLW/Perf-Insight-Report,zeptonaut/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,SummerLW/Perf-Insight-Report,danbeam/catapult,scottmcmaster/catapult,modulexcite/catapult,catapult-project/catapult,dstockwell/catapult,catapult-project/catapult,catapult-project/catapult-csm,sahiljain/catapult,modulexcite/catapult,catapult-project/catapult,0x90sled/catapult,catapult-project/catapult,catapult-project/catapult,zeptonaut/catapult,scottmcmaster/catapult,catapult-project/catapult-csm,danbeam/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult-csm,benschmaus/catapult,0x90sled/catapult,benschmaus/catapult,catapult-project/catapult,sahiljain/catapult,dstockwell/catapult,benschmaus/catapult,danbeam/catapult,sahiljain/catapult,dstockwell/catapult,SummerLW/Perf-Insight-Report,benschmaus/catapult,0x90sled/catapult,zeptonaut/catapult,sahiljain/catapult,catapult-project/catapult-csm,danbeam/catapult,benschmaus/catapult,catapult-project/catapult-csm,scottmcmaster/catapult,sahiljain/catapult,modulexcite/catapult