[css-inline][css-text][css-pseudo] Define more details of the "first formatted line" #10990
Description
Discussing on wpt tests for text-box-trim with @fantasai raised questions about the first formatted line.
Currently, the ::first-line pseudo-element and the text-indent property use this definition.
This test@jsbin indicates that browsers use different criteria for the "first formatted line".
| Test | Gecko | WebKit | Blink | |
|---|---|---|---|---|
| Content in a nested div | text-indent | Yes | Yes | Yes |
| ::first-line | No | Yes | Yes | |
| An empty div before content | text-indent | No | No | No |
| ::first-line | No | No | No | |
| An empty div before nested content | text-indent | Yes | Yes | Yes |
| ::first-line | No | No | No | |
| An empty div with an empty line before nested content | text-indent | Yes | Yes | Yes |
| ::first-line | No | No | No | |
| An empty anonymous block with an empty line before nested content | text-indent | Yes | Yes | Yes |
| ::first-line | No | Yes | No | |
Can we define the desired behavior for these cases?
@fantasai @nt1m @vitorroriz @Clqsin45 @bfgeek @lilles @jfkthame