[css-inline-3] Alternative initial-letter-align based on glyph bounds

Kindle has had a version of initial-letter implemented for several years, but the default alignment follows a behavior which doesn't seem possible with the initial-letter spec. Instead of using font-wide metrics for alignment, it measures the specific glyph bounds of the text under initial-letter. It then can align the lowest point of the glyph with the baseline of the body text.

The behavior can be viewed in our KindleCreate app (image below):

You can see the initial-letter (or drop cap as it's called here) actually takes up the 3 lines that are specified by the author. While a similar implementation in Safari would take up 4 since the descender knocks out an extra line.

I'm working on asking some of publisher contacts what the expected behavior would be when characters with descenders are used with initial-letter, but in the meantime wanted to get a feel for other people's thoughts here.

Review the issue description and its screenshots, then compare the described KindleCreate behavior with the CSS initial-letter specification and Safari behavior. The open question is how initial-letter should align when glyph bounds, including descenders, differ from font-wide metrics; completion would require agreement on the intended behavior and a corresponding specification change.