Empty button baseline difference in IE/Firefox and WebKit browsers

Hi,

Here is yet another interoperability issue we've found during IE compatibility investigations, that I would like to clarify with working group.

Consider the following simplified example - http://jsfiddle.net/x2vgt1xz/ - it looks to me that IE/Firefox sets empty element baseline as if the button had a content inside, while it looks like Chrome is treating the empty button as an empty inline element.

We have encountered this on http://www.sportsauthority.com - the site tries to fix this for WebKit browsers with a rule offsetting title by negative 10 pixels:

@media screen and (-webkit-min-device-pixel-ratio: 0) {
#header #utility #sli_search_1 {
                position: relative;
                top: -10px;
}
}

Which browsers behaves correctly and per spec in this case? Or is this one of the areas left to UA that has compatibility constraints for some legacy content?