Add tests for timers in background isolates in Dartium.

tests/html/async_test.dart

 library async_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
 
 import 'dart:async';
 import 'dart:isolate';
 import 'dart:html';
 
-oneshotTimerIsolate(message) {
-  var command = message[0];
-  var replyTo = message[1];
-  expect(command, 'START');
-  new Timer(const Duration(milliseconds: 10), () {
-    replyTo.send('DONE');
-  });
-}
+import 'async_oneshot.dart' as oneshot_test show main; 
+import 'async_periodictimer.dart' as periodictimer_test show main;
+import 'async_cancellingisolate.dart' as cancelling_test show main;
 
-periodicTimerIsolate(message) {
-  var command = message[0];
-  var replyTo = message[1];
-  expect(command, 'START');
-  int counter = 0;
-  new Timer.periodic(const Duration(milliseconds: 10), (timer) {
-    if (counter == 3) {
-      counter = 1024;
-      timer.cancel();
-      // Wait some more time to be sure callback won't be invoked any
-      // more.
-      new Timer(const Duration(milliseconds: 30), () {
-        replyTo.send('DONE');
-      });
-      return;
-    }
-    assert(counter < 3);
-    counter++;
-  });
-}
-
-cancellingIsolate(message) {
-  var command = message[0];
-  var replyTo = message[1];
-  expect(command, 'START');
-  bool shot = false;
-  var oneshot;
-  var periodic;
-  periodic = new Timer.periodic(const Duration(milliseconds: 10), (timer) {
-    expect(shot, isFalse);
-    shot = true;
-    expect(timer, same(periodic));
-    periodic.cancel();
-    oneshot.cancel();
-    // Wait some more time to be sure callbacks won't be invoked any
-    // more.
-    new Timer(const Duration(milliseconds: 50), () {
-      replyTo.send('DONE');
-    });
-  });
-  // We launch the oneshot timer after the periodic timer. Otherwise a
-  // (very long) context switch could make this test flaky: assume the
-  // oneshot timer is created first and then there is a 30ms context switch.
-  // when the periodic timer is scheduled it would execute after the oneshot.
-  oneshot = new Timer(const Duration(milliseconds: 30), () {
-    fail('Should never be invoked');
-  });
-}
+oneshot(message) => oneshot_test.main(message.first, message.last);
+periodicTimerIsolate(message) =>
+    periodictimer_test.main(message.first, message.last);
+cancellingIsolate(message) => cancelling_test.main(message.first, message.last);
 
 main() {
   useHtmlConfiguration();
 
   test('one shot timer in pure isolate', () {
     var response = new ReceivePort();
-    var remote = Isolate.spawn(oneshotTimerIsolate,
-                               ['START', response.sendPort]);
+    var remote = Isolate.spawn(oneshot,
+                               [['START'], response.sendPort]);
     expect(remote.then((_) => response.first), completion('DONE'));
   });
+
   test('periodic timer in pure isolate', () {
     var response = new ReceivePort();
     var remote = Isolate.spawn(periodicTimerIsolate,
-                               ['START', response.sendPort]);
+                               [['START'], response.sendPort]);
     expect(remote.then((_) => response.first), completion('DONE'));
   });
+  
   test('cancellation in pure isolate', () {
     var response = new ReceivePort();
     var remote = Isolate.spawn(cancellingIsolate,
-                               ['START', response.sendPort]);
+                               [['START'], response.sendPort]);
     expect(remote.then((_) => response.first), completion('DONE'));
   });
 }