The detailed story was in https://bugs.webkit.org/show_bug.cgi?id=50386.
Echo Alexey's suggestion, add a layout test to avoid future regressions.
Creating this bug is about to track the patch.
Created attachment 75590 [details]
Comment on attachment 75590 [details]
It's confusing that the result is written out at the end of each stage - it's only the second write that matters.
Created attachment 75600 [details]
(In reply to comment #2)
> (From update of attachment 75590 [details])
> It's confusing that the result is written out at the end of each stage - it's only the second write that matters.
You are right, I think the test should stop once it encounters a failure.
Here is the new patch, please take a look:)
The commit-queue encountered the following flaky tests while processing attachment 75600 [details]:
Please file bugs against the tests. These tests were authored by firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, and firstname.lastname@example.org. The commit-queue is continuing to process your patch.
Comment on attachment 75600 [details]
Clearing flags on attachment: 75600
Committed r73327: <http://trac.webkit.org/changeset/73327>
All reviewed patches have been landed. Closing bug.