Created attachment 174432 [details] Test file Because of rounding issues the rendering in regions when using subpixel layout is not similar to the reference. See the attached test file.
Created attachment 174433 [details] Reference for test
Works for me on today's nightly (r151543)
As long as the sub-pixel layout code is still in WebKit (even if it's disabled in the Mac port), the bug should still be open.
VERIFIED
CSS Regions were removed in Bug 174978.