Second version of support for specifying an unhandled exception callback

runtime/lib/isolate_patch.dart

 // Copyright (c) 2012, 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.
 
 patch class ReceivePort {
   /* patch */ factory ReceivePort() {
     return new _ReceivePortImpl();
   }
 }
 
@@ skipping 105 matching lines @@
 
 ReceivePort _portInternal;
 
 patch ReceivePort get port {
   if (_portInternal == null) {
     _portInternal = _getPortInternal();
   }
   return _portInternal;
 }
 
-patch spawnFunction(void topLevelFunction()) native "isolate_spawnFunction";
+patch spawnFunction(void topLevelFunction(),
+    [bool UnhandledExceptionCallback(IsolateUnhandledException e)]) 
+    native "isolate_spawnFunction";
 
 patch spawnUri(String uri) native "isolate_spawnUri";
 
 patch class Timer {
   /* patch */ factory Timer(int milliseconds, void callback(Timer timer)) {
     if (_TimerFactory._factory == null) {
       throw new UnsupportedError("Timer interface not supported.");
     }
     return _TimerFactory._factory(milliseconds, callback, false);
   }
@@ skipping 17 matching lines @@
 
 class _TimerFactory {
   static _TimerFactoryClosure _factory;
 }
 
 // TODO(ahe): Warning: this is NOT called by Dartium. Instead, it sets
 // [_TimerFactory._factory] directly.
 void _setTimerFactoryClosure(_TimerFactoryClosure closure) {
   _TimerFactory._factory = closure;
 }