The following layout test timeout sometimes on platform GTK:
Sorry.. I meant that it fails sometimes (no timeouts).
When it fails, the failure is the following: http://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r171130%20%281443%29/inspector-protocol/debugger/setBreakpoint-dfg-and-modify-local-pretty-diff.html
Running the test in a loop until it fails should be enough to reproduce the failure. It looks like a race condition somewhere
I have marked this test on the GTK TestExpectations on r171169 <http://trac.webkit.org/r171169>
This happens on the Mac too, with the same diff. Will move the expectation to cross-platform file.