Add more flaky timeline tests.
Add more flaky timeline tests.

BUG=407915
TBR=hclam@chromium.org

Review URL: https://codereview.chromium.org/532623002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@181214 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs