Make NodeList methods return NodeLists rather than List<Node>.

client/tests/client/html/NodeTests.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 
 Node makeNode() => new Element.tag('div');
 Node makeNodeWithChildren() =>
   new Element.html("<div>Foo<br/><!--baz--></div>");
 
 void testNode() {
   group('nodes', () {
+    test('is a NodeList', () {
+      Expect.isTrue(makeNodeWithChildren().nodes is NodeList);
+    });
+
     test('first', () {
       var node = makeNodeWithChildren();
       Expect.isTrue(node.nodes.first is Text);
     });
 
     test('last', () {
       var node = makeNodeWithChildren();
       Expect.isTrue(node.nodes.last() is Comment);
     });
 
     test('forEach', () {
       var nodes = [];
       var node = makeNodeWithChildren();
       node.nodes.forEach((n) => nodes.add(n));
       Expect.isTrue(nodes[0] is Text);
       Expect.isTrue(nodes[1] is BRElement);
       Expect.isTrue(nodes[2] is Comment);
     });
 
     test('filter', () {
       var filtered = makeNodeWithChildren().nodes.filter((n) => n is BRElement);
       Expect.equals(1, filtered.length);
       Expect.isTrue(filtered[0] is BRElement);
+      Expect.isTrue(filtered is NodeList);
     });
 
     test('every', () {
       var node = makeNodeWithChildren();
       Expect.isTrue(node.nodes.every((n) => n is Node));
       Expect.isFalse(node.nodes.every((n) => n is Comment));
     });
 
     test('some', () {
       var node = makeNodeWithChildren();
@@ skipping 70 matching lines @@
       Expect.listEquals([], node.nodes);
     });
 
     test('removeLast', () {
       var node = makeNodeWithChildren();
       Expect.isTrue(node.nodes.removeLast() is Comment);
       Expect.equals(2, node.nodes.length);
       Expect.isTrue(node.nodes.removeLast() is BRElement);
       Expect.equals(1, node.nodes.length);
     });
+
+    test('getRange', () {
+      var node = makeNodeWithChildren();
+      Expect.isTrue(node.nodes.getRange(1, 2) is NodeList);
+    });
+  });
+
+  group('_NodeList', () {
+    NodeList makeNodeList() =>
+      makeNodeWithChildren().nodes.filter((_) => true);
+
+    test('first', () {
+      var nodes = makeNodeList();
+      Expect.isTrue(nodes.first is Text);
+    });
+
+    test('filter', () {
+      var filtered = makeNodeList().filter((n) => n is BRElement);
+      Expect.equals(1, filtered.length);
+      Expect.isTrue(filtered[0] is BRElement);
+      Expect.isTrue(filtered is NodeList);
+    });
+
+    test('getRange', () {
+      var range = makeNodeList().getRange(1, 2);
+      Expect.isTrue(range is NodeList);
+      Expect.isTrue(range[0] is BRElement);
+      Expect.isTrue(range[1] is Comment);
+    });
   });
 }