Advance html5lib to newest breaking changes in core: getKeys -> keys, etc

lib/src/list_proxy.dart

 // TODO(jmesserly): remove this once we have a subclassable growable list
 // in our libraries.
 
 /** A [List] proxy that you can subclass. */
 library list_proxy;
 
 // TODO(jmesserly): this should extend the base list.
 // See http://code.google.com/p/dart/issues/detail?id=949
 /** A [List<T>] proxy that you can subclass. */
 class ListProxy<E> implements List<E> {
@@ skipping 33 matching lines @@
   List<E> getRange(int start, int length) => _list.getRange(start, length);
   void forEach(void f(E element)) => _list.forEach(f);
   Collection map(f(E element)) => _list.map(f);
   reduce(initialValue, combine(previousValue, E element)) =>
       _list.reduce(initialValue, combine);
 
   Collection<E> filter(bool f(E element)) => _list.filter(f);
   bool every(bool f(E element)) => _list.every(f);
   bool some(bool f(E element)) => _list.some(f);
   bool get isEmpty => _list.isEmpty;
-  E last() => _list.last();
+  E get last => _list.last;
 
   set length(int value) { _list.length = value; }
   operator []=(int index, E value) { _list[index] = value; }
   void add(E value) { _list.add(value); }
   void addLast(E value) { _list.addLast(value); }
   void addAll(Collection<E> collection) { _list.addAll(collection); }
   void sort([compare = Comparable.compare]) {
     _list.sort(compare);
   }
   void clear() { _list.clear(); }
   E removeAt(int index) {
     // TODO(jmesserly): removeAt not implemented on the VM?
     var result = _list[index];
     _list.removeRange(index, 1);
     return result;
   }
   E removeLast() => _list.removeLast();
   void setRange(int start, int length, List<E> from, [int startFrom]) {
     _list.setRange(start, length, from, startFrom);
   }
   void removeRange(int start, int length) { _list.removeRange(start, length); }
   void insertRange(int start, int length, [E initialValue]) {
     _list.insertRange(start, length, initialValue);
   }
 }