Change Future.timeout callback to a named parameter.

tests/lib/async/timer_test.dart

Index: tests/lib/async/timer_test.dart
diff --git a/tests/lib/async/timer_test.dart b/tests/lib/async/timer_test.dart
index cbb317cd07ac12e0f104e99d3ae1336390bffeed..057d3a7ee117ab621f7ed329126a480c61c18113 100644
--- a/tests/lib/async/timer_test.dart
+++ b/tests/lib/async/timer_test.dart
@@ -18,7 +18,7 @@ int iteration;
 // Some browsers (Firefox and IE so far) can trigger too early. Add a safety
 // margin. We use identical(1, 1.0) as an easy way to know if the test is
 // compiled by dart2js.
-int get safetyMargin => identical(1, 1.0) ? 100 : 1;
+int get safetyMargin => identical(1, 1.0) ? 100 : 0;
 
 void timeoutHandler() {
   int endTime = (new DateTime.now()).millisecondsSinceEpoch;