Apparently textBaseline is not interoperable. Firefox implements the HTML Standard, but at least Chrome and Safari do not.

Bugs:

• https://bugzilla.mozilla.org/show_bug.cgi?id=737852
• https://bugs.chromium.org/p/chromium/issues/detail?id=607053

Questions:

• What is the desirable behavior?
• Do we have web-platform-tests?