Take a peek at the history of this test:
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=storage%2Findexeddb%2Fpending-version-change-stuck.html
circa 10/19/2016 the test goes from flaky timeouts to timing out most of the time. Unfortunately, since the test has been flaky for a long time we didn't catch this. :(
The revision range around the change includes https://chromium.googlesource.com/chromium/src/+/627e7f73d47910f4255031de55075e2a04b222f6)
The test attempts to exercise this:
(1) In a window, open a connection w/ version = 1
(2) Have a worker try to open a connection w/ version = 2 - this will be blocked
(3) Navigate the page (it does this using a reload to `?second` just because that's how layout tests do things) which should close the window's connection and worker's attempt
(4) Try and open a connection w/ version = 1
The test never succeeds following the Mojo change; the reload is somehow failing to let the IndexedDBDatabase instance know that the initial window's (??) connection is gone. (I think I see the worker's connection closing??) That was previously done via the dispatcher host, so it's unsurprising that the Mojo change might have affected this.
Comment 1 by reillyg@chromium.org
, Oct 28 2016