Patchset 6 of https://chromium-review.googlesource.com/c/527038/ has a test that's flaky (headless_browsertests --gtest_filter=ExperimentalCommandJsBindingsTest.RunAsyncTest).  It uses Page.getResourceTree to obtain the resources.  Usually it returns Ahem.ttf, dom_tree_test.css & dom_tree_test.html however about 1 time in 3 it returns only Ahem.ttf.

This appears to be because oilpan removed some elements from ResourceFetcher::document_resources_.  This means that Page.getResourceTree can't be relied upon (NB this isn't a problem for Headless I'll just change the test to use some other command).