<div class="flexbox" style="width: 4em; height: 4em; background: silver"> <p id="ok" style="margin: auto; font-family: Ahem">OK</p> </div> and <div style="width: 4em; height: 4em; background: silver"> <table style="width: 100%; height: 100%;"><tr><td style="text-align: center; font-family: Ahem;">OK</td></tr></table> </div> are not compatible when it comes to inline content vertical positioning due to the different rounding strategies (at block level). This test fails for example when font-size is set to 20px.
Created attachment 411183 [details] swapping between test and expected
<rdar://problem/70464703>
This seems to have progressed
Created attachment 452885 [details] Patch
Committed r290385 (247700@main): <https://commits.webkit.org/247700@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 452885 [details].