Making ScriptProcessorNode not an EventTarget.

tests/html/audiocontext_test.dart

Index: tests/html/audiocontext_test.dart
diff --git a/tests/html/audiocontext_test.dart b/tests/html/audiocontext_test.dart
index 33a7907181e09937bb7bcd291cbb7fd9a9700223..bcb0c8ab258443d9d9034c9000ef5efd98843b9d 100644
--- a/tests/html/audiocontext_test.dart
+++ b/tests/html/audiocontext_test.dart
@@ -3,6 +3,7 @@ import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
 import 'dart:web_audio';
+import 'dart:async';
 
 main() {
 
@@ -41,4 +42,19 @@ main() {
     expect(context.createPanner() is PannerNode, isTrue);
     expect(context.createScriptProcessor(4096) is ScriptProcessorNode, isTrue);
   });
+
+  test('onAudioProcess', () {
+    var context = new AudioContext();
+    var scriptProcessor = context.createScriptProcessor(1024, 1, 2);
+    scriptProcessor.connect(context.destination, 0, 0);
+    var completer = new Completer<bool>();
+    bool alreadyCalled = false;
+    scriptProcessor.onAudioProcess = (event) {
+      if (!alreadyCalled) {
+        completer.complete(true);
+      }
+      alreadyCalled = true;
+    };
+    return completer.future;
+  });
 }