dom library Null safety

A simple tree API that results from parsing html. Intended to be compatible with dart:html, but it is missing many types and APIs.

Classes

AttributeName
Comment
CssClassSet
A Set that stores the CSS class names for an element.
Document
DocumentFragment
DocumentType
Element
FilteredElementList
An indexable collection of a node's descendants in the document tree, filtered so that only elements are in the collection.
Node
Really basic implementation of a DOM-core like Node.
NodeList
Text