[css-inline-3] should non-replaced inline elements in phantom line boxes have their block-size adjusted to zero?

[dbaron]

In phantom line boxes (see level 3 definition, level 2 definition) there can be non-replaced inline elements. These elements' block-size (typically height) can matter for things like looking at offsetHeight. The spec section on phantom line boxes says no height adjustments occur; however, Chromium and WebKit both adjust such heights, but Gecko does not. See testcase (and look at the log section).

It's possible we should specify this height adjustment behavior; some content may depend on it.

[fantasai]

If Gecko doesn't, then possibly both behaviors are compatible, and we need to figure out which is preferable.