Timer callback doesn't take an argument anymore.

Review URL: https://codereview.chromium.org//12380019

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@19221 260f80e4-7a28-3924-810f-c04153c831b5

lib/src/io.dart

@@ -593,7 +593,7 @@ Future _doProcess(Function fn, String executable, List<String> args,
 Future timeout(Future input, int milliseconds, String description) {
   bool completed = false;
   var completer = new Completer();
-  var timer = new Timer(new Duration(milliseconds: milliseconds), (_) {
+  var timer = new Timer(new Duration(milliseconds: milliseconds), () {
     completed = true;
     completer.completeError(new TimeoutException(
         'Timed out while $description.'));