The ChromeBrowserMainBrowserTest.VariationsServiceStartsRequestOnNetworkChange test performs a real Variations request in order to check a request is performed upon network changes. To make the test more resilient to unrelated changes it should instead use a mock of the service that just registers when it attempts a fetch, similar to the TestVariationsService used in other tests (https://cs.chromium.org/chromium/src/components/variations/service/variations_service_unittest.cc?rcl=47f35a3192cb23183bb07f35aa5d50da31ab0e98&l=114)