Copy lib/dom tests that use dart:html to lib/html.

tests/dom/isolates_test.dart

-#library('IsolatesTest');
-#import('../../lib/unittest/unittest.dart');
-#import('../../lib/unittest/html_config.dart');
-#import('dart:html');
-#import('dart:json');
-#import('dart:isolate', prefix:'isolate');
-
-class PingPongIsolate extends isolate.Isolate {
-  PingPongIsolate() : super.heavy();
-
-  void main() {
-    bool wasThrown = false;
-    try {
-      window.alert('Test');
-    } catch(final e) {
-      wasThrown = true;
-    }
-    // If wasn't thrown, do not listen to messages to make test fail.
-    if (!wasThrown) {
-      return;
-    }
-
-    // Check that JSON library was loaded to isolate.
-    JSON.stringify([1, 2, 3]);
-
-    port.receive((message, replyTo) {
-      replyTo.send(responseFor(message), null);
-    });
-  }
-
-  static String responseFor(message) => 'response for $message';
-}
-
-main() {
-  useHtmlConfiguration();
-  asyncTest('IsolateSpawn', 1, () {
-    new PingPongIsolate().spawn().then((isolate.SendPort port) {
-      callbackDone();
-    });
-  });
-  asyncTest('NonDOMIsolates', 1, () {
-    new PingPongIsolate().spawn().then((isolate.SendPort port) {
-      final msg1 = 'foo';
-      final msg2 = 'bar';
-      port.call(msg1).then((response) {
-        Expect.equals(PingPongIsolate.responseFor(msg1), response);
-        port.call(msg2).then((response) {
-          Expect.equals(PingPongIsolate.responseFor(msg2), response);
-          callbackDone();
-        });
-      });
-    });
-  });
-}