IDL dictionary members are nullable by default (unless marked as
`required`) and should not get any value assigned unless one was
provided by the userland code that isn't undefined, or if the member has
a default value.
This is so that we can use Optional<T> in the internal representation
and check for "is present" via Optional::has_value().
The SourceGenerator's @else@ mapping is only set in the second iteration
of the loop, causing the generated return for unrecognized values to not
be guarded by an else statement.
We can simply use a hardcoded 'else' here, @else@ is only to create the
first comparison as a plain 'if' and subsequent ones as 'else if'.
Without this, the generated DOMExceptionConstructor does not refer to
the WebIDL::DOMException with its fully qualified name. This caused an
ambiguity error on my machine.
Let's stop putting generic types and AOs from the Web IDL spec into
the Bindings namespace and directory in LibWeb, and instead follow our
usual naming rules of 'directory = namespace = spec name'. The IDL
namespace is already used by LibIDL, so Web::WebIDL seems like a good
choice.
This code generator no longer creates JS wrappers for platform objects
in the old sense, instead they're JS objects internally themselves.
Most of what we generate now are prototypes - which can be seen as
bindings for the internal C++ methods implementing getters, setters, and
methods - as well as object constructors, i.e. bindings for the internal
create_with_global_object() method.
Also tweak the naming of various CMake glue code existing around this.
