[css-text-decor] [css-pseudo] text-decoration-line:: spelling-error inside ::spelling-error pseudo (and grammar)

[schenney-chromium]

It was resolved in #7522 to ignore all other text-decoration properties when the text-decoration-lineproperty has value spelling-error or grammar-error.

When ''spelling-error'' or ''grammar-error'' apply, the user agent must disregard the other sub-properties of 'text-decoration', as well any other properties typically affecting the appearance of line decorations (such as 'text-underline-position', 'color', 'stroke', or 'fill') when rendering these decorations.

A side effect of this change is that

::spelling-error { text-decoration-color: blue; }

has no effect because the default text-decoration-line for ::spelling-error is spelling-error (as one would hope).

Same applies to ::grammar-error.

I propose that we accept this as working as intended, and update the spec to clearly say that ::spelling-error will only respect text decoration properties when text-decoration-line is present with a value other than spelling-error or grammar-error.

::spelling-error {
   text-decoration-line: underline;
   text-decoration-style: wavy;
   text-decoration-color: blue;
}

[schenney-chromium]

@fantasai is the intent to say, yes, this is working as intended and update the spec as necessary?

[schenney-chromium]

PR to do the edit: #9633