[functions] Support @media within @function

This adds support for "functional" media queries, which evaluate
during value computation rather than during RuleSet building.
Although it would probably be possible to also handle @media
within @function on the rule level rather than value level,
the value level approach was chosen since it will be required
anyway for the if() notation in the future [1].

Since the existing invalidation path for @media is RuleSet based,
this CL implements a new invalidation strategy:

 - ComputedStyles affected by functional media are marked as such.
 - Functional MQs are evaluated during StyleCascade, and the results
   are stored on StyleEngine.
 - When media values change, we check the stored results for changes.
   If there was a change in evaluation, we invalidate all elements
   marked as affected by functional media.

It is possible invalidate even more narrowly, e.g. track which
specific elements depend on which specific media queries, but for now
this seems to strike a reasonable balance.

StyleEngine must also keep track of some flags from the functional
MQ evaluation, otherwise ParentLayoutUpgrade will not understand that
there is a parent frame dependency.

[1] https://drafts.csswg.org/css-values-5/#if-notation

Bug: 325504770
Change-Id: I5ac00afc165826e9ce7789fba7fa6e4f0d6c0bf6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6234272
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1417299}