The following layout test is failing on GTK editing/caret/color-span-inside-editable-background.html Probable cause: As result shows, small amount of descender of text was clipped by the editable element. This test can be treated as passed, but this clipping make visual artifacts. Test result: https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r175152%20%283727%29/editing/caret/color-span-inside-editable-background-diffs.html
The following layout test is also failing with similar behavior. fast/layers/parent-clipping-overflow-is-overwritten-by-child-clipping.html The small amount of descender area of text is clipped also. https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r174986%20%283642%29/fast/layers/parent-clipping-overflow-is-overwritten-by-child-clipping-diffs.html
This started to pass after the freetype upgrade in r221670