Pixel tests fail all over the place on OS X 10.10 because the generated results are 1600x1200 instead of 800x600.
Bots don't catch this, because they don't have Retina screens.
Created attachment 243648 [details]
Comment on attachment 243648 [details]
Looks like this isn't right, I'm told that hidpi tests on Yosemite become broken.
*** Bug 140125 has been marked as a duplicate of this bug. ***
Created attachment 244176 [details]