This reftest doesn't work on MacOS 10.8: http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fast%2Fregions%2Fautoheight-definedheight-changenotdetected.html
Already taken a look without being able to reproduce it, but i may have a potential fix for it.
Created attachment 172226 [details] Patch I suspect turning off font-smoothing for the Ahem font used for content that is flowed into regions will fix the problem. I was not able to reproduce the problem on my ML machine.
Comment on attachment 172226 [details] Patch I'm a bit skeptical but let's try that.
Comment on attachment 172226 [details] Patch Looking at the actual result more closely, this might be a real bug in Chromium. Let's hold off on landing this. http://build.chromium.org/f/chromium/layout_test_results/WebKit_Mac10_8/results/layout-test-results/fast/regions/autoheight-definedheight-changenotdetected-actual.png
Emil & Levi, Is 1px anti-aliasing showing up on the boxes on the left and the bottom right expected? I can't help but think that this is a real bug in Chromium on 10.8.
(In reply to comment #5) > Emil & Levi, > > Is 1px anti-aliasing showing up on the boxes on the left and the bottom right expected? I can't help but think that this is a real bug in Chromium on 10.8. Depends on what the test is doing, hard to tell from the screenshot.
(In reply to comment #6) > (In reply to comment #5) > > Emil & Levi, > > > > Is 1px anti-aliasing showing up on the boxes on the left and the bottom right expected? I can't help but think that this is a real bug in Chromium on 10.8. > > Depends on what the test is doing, hard to tell from the screenshot. The test is using a 50px Ahem to create a green line. Independent of regions, i have noticed that a simple div using a 50px Ahem font has the same antialiasing, which is gone if one specifies -webkit-font-smoothing: none, hence my proposed fix for the test in Chromium.