Rework Timer interface.

tests/isolate/timer_cancel1_test.dart

Index: tests/isolate/timer_cancel1_test.dart
diff --git a/tests/isolate/timer_cancel1_test.dart b/tests/isolate/timer_cancel1_test.dart
index efcbbe8cb1816ad7e7bc36b49cd6f8bb3180a4d0..61bb5dd7409c22cb8a072f6da9db04c57ce0c0bd 100644
--- a/tests/isolate/timer_cancel1_test.dart
+++ b/tests/isolate/timer_cancel1_test.dart
@@ -12,15 +12,17 @@ main() {
     var canceleeTimer;
     var cancelerTimer;
 
-    void unreachable(Timer timer) {
+    void unreachable() {
       fail("A canceled timeout handler should be unreachable.");
     }
 
-    void handler(Timer timer) {
+    void handler() {
       canceleeTimer.cancel();
     }
 
-    cancelerTimer = new Timer(1, expectAsync1(handler));
-    canceleeTimer = new Timer(1000, expectAsync1(unreachable, count: 0));
+    cancelerTimer = new Timer(const Duration(milliseconds: 1),
+                              expectAsync0(handler));
+    canceleeTimer = new Timer(const Duration(milliseconds: 1000),
+                              expectAsync0(unreachable, count: 0));
   });
 }