Describe the problem:

I want to pass a command line flag to the browser executing a benchmark. I can do that through the pinpoint "Run a try job" dialog by adding "--extra-browser-args=" to the "Extra Test Arguments" text field. But there is no such option when I'm running bisect from the performance dashboard. 

"Request debug trace" dialog in the performance dashboard allows to modify only chrome trace filter string. It would be nice to add "Extra Test Arguments" parameter there.