Make hasNext a getter instead of a method.

lib/html/src/_ListIterators.dart

Index: lib/html/src/_ListIterators.dart
diff --git a/lib/html/src/_ListIterators.dart b/lib/html/src/_ListIterators.dart
index 2eb9acc592ea56f37273e873fbcef1b2d099f80f..039eda61c645951468972ba5abc0c40892e79406 100644
--- a/lib/html/src/_ListIterators.dart
+++ b/lib/html/src/_ListIterators.dart
@@ -8,7 +8,7 @@ class _FixedSizeListIterator<T> extends _VariableSizeListIterator<T> {
       : super(array),
         _length = array.length;
 
-  bool hasNext() => _length > _pos;
+  bool get hasNext => _length > _pos;
 
   final int _length;  // Cache array length for faster access.
 }
@@ -19,10 +19,10 @@ class _VariableSizeListIterator<T> implements Iterator<T> {
       : _array = array,
         _pos = 0;
 
-  bool hasNext() => _array.length > _pos;
+  bool get hasNext => _array.length > _pos;
 
   T next() {
-    if (!hasNext()) {
+    if (!hasNext) {
       throw const NoMoreElementsException();
     }
     return _array[_pos++];