Adding annotation for partial browser support and example implementation for MutationObservers.

tests/html/mutationobserver_test.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.
 
 library mutationobserver_test;
 import '../../pkg/unittest/lib/unittest.dart';
-import '../../pkg/unittest/lib/html_config.dart';
+import '../../pkg/unittest/lib/html_individual_config.dart';
 import 'dart:html';
 
 /**
  * Test suite for Mutation Observers. This is just a small set of sanity
  * checks, not a complete test suite.
  */
 main() {
-  useHtmlConfiguration();
+  useHtmlIndividualConfiguration();
+
+  group('supported', () {
+    test('supported', () {
+      expect(MutationObserver.supported, true);
+    });
+  });
+
+  var expectation = MutationObserver.supported ? returnsNormally : throws;
 
   group('childList', () {
-
     mutationCallback(count, expectation) {
       var done = false;
       var nodes = [];
 
       callback(mutations, observer) {
         for (MutationRecord mutation in mutations) {
           for (Node node in mutation.addedNodes) {
             nodes.add(node);
           }
         }
         if (nodes.length >= count) {
           done = true;
           expect(nodes.length, count);
           expect(nodes, expectation);
         }
       }
 
+      // If it's not supported, don't block waiting for it.
+      if (!MutationObserver.supported) {
+        return () => done;
+      }
+
       return expectAsyncUntil2(callback, () => done);
     }
 
     test('empty options is syntax error', () {
+      expect(() {
         var mutationObserver = new MutationObserver(
             (mutations, observer) { expect(false, isTrue,
                 reason: 'Should not be reached'); });
         expect(() { mutationObserver.observe(document, {}); },
                throws);
-      });
+      }, expectation);
+    });
 
     test('direct-parallel options-map', () {
+      expect(() {
         var container = new DivElement();
         var div1 = new DivElement();
         var div2 = new DivElement();
         var mutationObserver = new MutationObserver(
             mutationCallback(2, orderedEquals([div1, div2])));
         mutationObserver.observe(container, options: {'childList': true});
 
         container.nodes.add(div1);
         container.nodes.add(div2);
-      });
+      }, expectation);
+    });
 
     test('direct-parallel options-named', () {
+      expect(() {
         var container = new DivElement();
         var div1 = new DivElement();
         var div2 = new DivElement();
         var mutationObserver = new MutationObserver(
             mutationCallback(2, orderedEquals([div1, div2])));
         mutationObserver.observe(container, childList: true);
 
         container.nodes.add(div1);
         container.nodes.add(div2);
-      });
+      }, expectation);
+    });
 
     test('direct-nested options-named', () {
+      expect(() {
         var container = new DivElement();
         var div1 = new DivElement();
         var div2 = new DivElement();
         var mutationObserver =
             new MutationObserver(mutationCallback(1, orderedEquals([div1])));
         mutationObserver.observe(container, childList: true);
 
         container.nodes.add(div1);
         div1.nodes.add(div2);
-      });
+      }, expectation);
+    });
 
 
     test('subtree options-map', () {
+      expect(() {
         var container = new DivElement();
         var div1 = new DivElement();
         var div2 = new DivElement();
         var mutationObserver = new MutationObserver(
             mutationCallback(2, orderedEquals([div1, div2])));
         mutationObserver.observe(container,
                                  options: {'childList': true, 'subtree': true});
 
         container.nodes.add(div1);
         div1.nodes.add(div2);
-      });
+      }, expectation);
+    });
 
     test('subtree options-named', () {
+      expect(() {
         var container = new DivElement();
         var div1 = new DivElement();
         var div2 = new DivElement();
         var mutationObserver = new MutationObserver(
             mutationCallback(2, orderedEquals([div1, div2])));
         mutationObserver.observe(container, childList: true, subtree: true);
 
         container.nodes.add(div1);
         div1.nodes.add(div2);
-      });
+      }, expectation);
+    });
   });
 }