to make Findit support more test harness, it needs to be able to trigger swarming reruns for each test harness. 

At the time this bug is filed, Findit already supports gtest. And it will soon be able to support webkit_layout_tests.

The plan is to make changes at base_test_launcher to abstract away the difference in underlying test harness:
1. Get consensus on the names and expected behavior for the flags that Findit needs 
2. Change base_test_launcher to modify the flags based on the result of step 1
3. Make Findit to use the modified flags names
4. Make other test harness to use base_test_launcher

This is a metabug.