Currently, there are no Chromium tests to explicitly measure the reliability of Chrome startup. When there is any flakiness in Chrome startup, it usually shows up as flakiness in the tests for some other components. For example, in  issue #864205 , Chrome startup problems caused chromedriver_py_tests to be flaky. Instead, there should be a test with the explicit responsibility of measuring the reliability of Chrome startup, e.g., by repeatedly starting Chrome a large number of times.