Selectors like `:is(.valid, &!?!?!invalid)` need to keep the invalid
part around, even though it will never match, for a couple of reasons:
- Serialization needs to include them
- For nesting, we care if a `&` appeared anywhere in the selector, even
in an invalid part.
So this patch introduces an `Invalid` simple selector type, which simply
holds its original ComponentValues. We search through these looking for
`&`, and we dump them out directly when asked to serialize.
Note that this is the old CSS2 syntax, we don't support the CSS3 syntax
just yet. Also we don't actually implement the pseudo-elements, this is
really just to make the selectors distinct from the same ones without
these pseudo-elements.
This enables a nice warning in case a function becomes dead code. Also, in the
case of {Event,Node}WrapperFactory.cpp, the corresponding header was forgotten.
This would cause an issue later when we enable -Wmissing-declarations.
Is my clang-format misconfigured? Why is the diff for NodeWrapperFactory.cpp
so large?
LibWeb keeps growing and the Web namespace is filling up fast.
Let's put DOM stuff into Web::DOM, just like we already started doing
with SVG stuff in Web::SVG.
To prepare for fully qualified tag names, let's call this local_name.
Note that we still keep an Element::tag_name() around since that's what
the JS bindings end up calling into for the Element.tagName property.
Instead of creating extremely common FlyStrings like "id" and "class"
on demand every time they are needed, we now have AttributeNames.h,
which provides Web::HTML::AttributeNames::{id,class_}
This avoids a bunch of string allocations during selector matching.
It's still only a dummy as LibWeb doesn't have focused elements yet, but
at least now we don't treat "selector:focus" as just "selector".
This fixes an issue on google.com which was mostly grey - coming from
some menu item focus styles :^)
