Revert "dart2js native mixin application should extend 'Interface', not 'Object'"

tests/html/node_test.dart

Index: tests/html/node_test.dart
diff --git a/tests/html/node_test.dart b/tests/html/node_test.dart
index acab82a20bbc4c9cb01574efa0b13b273b004947..083478f87b04c33a9a9ab0c38956dec148f90093 100644
--- a/tests/html/node_test.dart
+++ b/tests/html/node_test.dart
@@ -335,81 +335,28 @@ main() {
     });
   });
 
-  group('NodeList', () {
-    // Tests for methods on the DOM class 'NodeList'.
-    //
-    // There are two interesting things that are checked here from the viewpoint
-    // of the dart2js implementation of a 'native' class:
-    //
-    //   1. Some methods are implementated from by 'Object' or 'Interceptor';
-    //      some of these tests simply check that a method can be called.
-    //   2. Some methods are implemented by mixins.
-
+  group('_NodeList', () {
     List<Node> makeNodeList() =>
-        (new Element.html("<div>Foo<br/><!--baz--><br/><br/></div>"))
-        .$dom_getElementsByTagName('br');
-
-    test('trueNodeList', () {
-      var nodes = makeNodeList();
-      expect(nodes is NodeList, true);
-    });
-
-    test('hashCode', () {
-      var nodes = makeNodeList();
-      var hash = nodes.hashCode;
-      final int N = 1000;
-      int matchCount = 0;
-      for (int i = 0; i < N; i++) {
-        if (makeNodeList().hashCode == hash) matchCount++;
-      }
-      expect(matchCount, lessThan(N));
-    });
-
-    test('operator==', () {
-      var a = [makeNodeList(), makeNodeList(), null];
-      for (int i = 0; i < a.length; i++) {
-        for (int j = 0; j < a.length; j++) {
-          expect(i == j,  a[i] == a[j]);
-        }
-      }
-    });
-
-    test('runtimeType', () {
-      var nodes1 = makeNodeList();
-      var nodes2 = makeNodeList();
-      var type1 = nodes1.runtimeType;
-      var type2 = nodes2.runtimeType;
-      expect(type1 == type2, true);
-      String name = '$type1';
-      if (name.length > 3) {
-        expect(name.contains('NodeList'), true);
-      }
-    });
+      makeNodeWithChildren().nodes.where((_) => true).toList();
 
     test('first', () {
       var nodes = makeNodeList();
-      expect(nodes.first, isBRElement);
-    });
-
-    test('last', () {
-      var nodes = makeNodeList();
-      expect(nodes.last, isBRElement);
+      expect(nodes.first, isText);
     });
 
     test('where', () {
       var filtered = makeNodeList().where((n) => n is BRElement).toList();
-      expect(filtered.length, 3);
+      expect(filtered.length, 1);
       expect(filtered[0], isBRElement);
       expect(filtered, isNodeList);
     });
 
     test('sublist', () {
       var range = makeNodeList().sublist(1, 3);
-      expect(range.length, 2);
+      expect(range, isNodeList);
       expect(range[0], isBRElement);
-      expect(range[1], isBRElement);
+      expect(range[1], isComment);
     });
-
   });
 
   group('iterating', () {