The upcoming generated types will match those for pseudo-classes: A
PseudoElementSelector type, that then holds a PseudoElement enum
defining what it is. That enum will be at the top level in the Web::CSS
namespace.
In order to keep the diffs clearer, this commit renames and moves the
types, and then a following one will replace the handwritten enum with
a generated one.
Previously, parse_css_style_attribute() would parse the string, extract
the properties, add them to a newly-created
ElementInlineCSSStyleDeclarations, and then user code would take the
properties back out of it again and throw it away. Instead, just return
the list of properties, and the caller can create an EICSD if it needs
one.
Instead of parsing the parts of a `@supports` query, then only
evaluating them when constructing the Supports itself, we can instead
evaluate them as we parse them. This simplifies things as we no longer
need to pass a Realm around, and don't have to re-parse the conditions
again with a new Parser instance.
This is not really a context, but more of a set of parameters for
creating a Parser. So, treat it as such: Rename it to ParsingParams,
and store its values and methods directly in the Parser instead of
keeping the ParsingContext around.
This has a nice side-effect of not including DOM/Document.h everywhere
that needs a Parser.
