Make hasNext a getter instead of a method.

lib/html/dartium/html_dartium.dart

Index: lib/html/dartium/html_dartium.dart
diff --git a/lib/html/dartium/html_dartium.dart b/lib/html/dartium/html_dartium.dart
index 04187a4641b5029fe7bc113eb6e98e40af4ba841..1b33acc7ddb21ca400e28b6c661a5ae6d7e4d0a8 100644
--- a/lib/html/dartium/html_dartium.dart
+++ b/lib/html/dartium/html_dartium.dart
@@ -12950,7 +12950,7 @@ class _FrozenElementListIterator implements Iterator<Element> {
    * [NoMoreElementsException] if no element is left.
    */
   Element next() {
-    if (!hasNext()) {
+    if (!hasNext) {
       throw const NoMoreElementsException();
     }
 
@@ -12960,7 +12960,7 @@ class _FrozenElementListIterator implements Iterator<Element> {
   /**
    * Returns whether the [Iterator] has elements left.
    */
-  bool hasNext() => _index < _list.length;
+  bool get hasNext => _index < _list.length;
 }
 
 class _ElementAttributeMap implements AttributeMap {
@@ -43058,7 +43058,7 @@ class _Collections {
   }
 
   static bool isEmpty(Iterable<Object> iterable) {
-    return !iterable.iterator().hasNext();
+    return !iterable.iterator().hasNext;
   }
 }
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
@@ -44003,7 +44003,7 @@ 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.
 }
@@ -44014,10 +44014,10 @@ 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++];