NodeTypeId is supposed to reflect the WebIDL inheritance hierarchy.
All of Text/ProcessingInstruction/Comment inherit from CharacterData,
which inherits from Node. There should be a CharacterDataTypeId value
that differentiates between those, instead.
This used to conflict with the util crate from the standard library, which
has long since been removed.
The import in layout has not been changed because of a conflict with the
util mod there.
Replace &JSRef with JSRef in the bulk of the generated code. This will
remove a level of indirection throughout all DOM code.
This patch doesn't change methods implemented on JSRef<T> to take `self`
rather than `&self`, and it leaves a few other uses of &JSRef, but those
changes can be made incrementally.