When replacing the data in `CharacterData`, we were only invalidating
text-dependent cache and layout of the layout node(s) corresponding to
that `CharacterData`. This is not sufficient: With `::first-letter`
styling, `TextSliceNode`s are being created for the first letter and the
remainder of the text. So, contrary to regular `TextNode`s, these store
offsets into the text data determined while building the layout tree.
Subsequently these become stale when only invalidating layout, but not
the layout tree. Using such stale offsets with updated text data leads
to crashes in `TextNode::compute_text_for_rendering()` if the text got
shorter and incorrect behavior if it got longer.
To fix this, invalidate the layout tree of the parent of the affected
`TextSliceNode`s, causing a rebuild that creates new slice nodes with
the updated data.
This fixes a crash when typing in the search box on
https://search.brave.com/ where a first-letter style is used to
capitalize the first letter of the search suggestions descriptions. This
crash was a regression from b67d73a661.
4ae31dc777