performance_browser_tests failing on chromium.perf/Win 7 ATI GPU Perf

Builders failed on: 
- Win 7 ATI GPU Perf: 
  https://build.chromium.org/p/chromium.perf/builders/Win%207%20ATI%20GPU%20Perf


Looks like this test has been flaky for a while

Failing runs:
https://chromium-swarm.appspot.com/task?id=388c6f95712e3210&refresh=10&show_raw=1
https://chromium-swarm.appspot.com/task?id=38951ddbab795c10&refresh=10&show_raw=1
https://chromium-swarm.appspot.com/task?id=387b1aa9b1634310&refresh=10&show_raw=1

Looks like one of the tests is taking too long and is timing out. miu@ can you take a look