The following layout test is flaky on at least Win and Linux (see http://test-results.appspot.com/dashboards/flakiness_dashboard.html#showExpectations=true&tests=inspector%2Fextensions%2Fextensions-events.html ): inspector/extensions/extensions-events.html It fails more consistently on Linux, but on both platforms, the symptom is that "Got onHidden event for sidebar" doesn't appear in the output.
For the FAIL cases (as opposed to TIMEOUT) it looks like http://trac.webkit.org/changeset/100145 is to blame.
I can't see an obvious culprit for the timeouts, so I'm assuming it's the same change. Will update expectations for now.
Committed r100435: <http://trac.webkit.org/changeset/100435>
Created attachment 115364 [details] Patch
Committed r100439: <http://trac.webkit.org/changeset/100439>