Use generic functions in zones.

tests/lib/async/zone_debug_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
 import 'dart:async';
 
 import 'dart:collection';
 
 /**
  * We represent the current stack trace by an integer. From time to time we
  * increment the variable. This corresponds to a new stack trace.
  */
 int stackTrace = 0;
 List restoredStackTrace = [];
 
 List events = [];
 
-debugZoneRegisterCallback(Zone self, ZoneDelegate parent, Zone origin, f()) {
+ZoneCallback<R> debugZoneRegisterCallback<R>(
+    Zone self, ZoneDelegate parent, Zone origin, R f()) {
   List savedTrace = [stackTrace]..addAll(restoredStackTrace);
   return parent.registerCallback(origin, () {
     restoredStackTrace = savedTrace;
     return f();
   });
 }
 
-debugZoneRegisterUnaryCallback(
-    Zone self, ZoneDelegate parent, Zone origin, f(arg)) {
+ZoneUnaryCallback<R, T> debugZoneRegisterUnaryCallback<R, T>(
+    Zone self, ZoneDelegate parent, Zone origin, R f(T arg)) {
   List savedTrace = [stackTrace]..addAll(restoredStackTrace);
   return parent.registerUnaryCallback(origin, (arg) {
     restoredStackTrace = savedTrace;
     return f(arg);
   });
 }
 
-debugZoneRun(Zone self, ZoneDelegate parent, Zone origin, f()) {
+T debugZoneRun<T>(Zone self, ZoneDelegate parent, Zone origin, T f()) {
   stackTrace++;
   restoredStackTrace = [];
   return parent.run(origin, f);
 }
 
-debugZoneRunUnary(Zone self, ZoneDelegate parent, Zone origin, f(arg), arg) {
+R debugZoneRunUnary<R, T>(
+    Zone self, ZoneDelegate parent, Zone origin, R f(T arg), T arg) {
   stackTrace++;
   restoredStackTrace = [];
   return parent.runUnary(origin, f, arg);
 }
 
 List expectedDebugTrace;
 
-debugUncaughtHandler(
+void debugUncaughtHandler(
     Zone self, ZoneDelegate parent, Zone origin, error, StackTrace stackTrace) {
   events.add("handling uncaught error $error");
   Expect.listEquals(expectedDebugTrace, restoredStackTrace);
   // Suppress the error and don't propagate to parent.
 }
 
 const DEBUG_SPECIFICATION = const ZoneSpecification(
     registerCallback: debugZoneRegisterCallback,
     registerUnaryCallback: debugZoneRegisterUnaryCallback,
     run: debugZoneRun,
@@ skipping 47 matching lines @@
       Expect.listEquals([fork2Trace, globalTrace], restoredStackTrace);
       fork3Trace = stackTrace;
       openTests--;
       if (openTests == 0) {
         done.complete();
       }
       scheduleMicrotask(() {
         expectedDebugTrace = [fork3Trace, fork2Trace, globalTrace];
         throw "gee";
       });
-    }, runGuarded: false);
-  }, runGuarded: false);
+    });
+  });
   openTests++;
   f();
   f2();
 
   done.future.whenComplete(() {
     // We don't really care for the order.
     events.sort();
     Expect.listEquals([
       "handling uncaught error bar",
       "handling uncaught error foo",
       "handling uncaught error gee"
     ], events);
     asyncEnd();
   });
 }