StartupLoadingMetricsTest* in chrome_public_test_apk is flaky.

Findit has detected 3 flake occurrences of tests below within
the past 24 hours:

org.chromium.chrome.browser.metrics.StartupLoadingMetricsTest#testStartWithURLRecorded
org.chromium.chrome.browser.metrics.StartupLoadingMetricsTest#testWebApkStartRecorded
org.chromium.chrome.browser.metrics.StartupLoadingMetricsTest#testNTPNotRecorded

Please try to find and revert the culprit if the culprit is obvious.
Otherwise please find an appropriate owner.