Fix audiocontext test

tests/html/audiocontext_test.dart

 library AudioContextTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_individual_config.dart';
 import 'dart:html';
+import 'dart:typeddata';
 import 'dart:web_audio';
 import 'dart:async';
 
 main() {
 
   useHtmlIndividualConfiguration();
 
   var isAudioContext =
       predicate((x) => x is AudioContext, 'is an AudioContext');
 
   group('supported', () {
     test('supported', () {
       expect(AudioContext.supported, true);
     });
   });
 
   group('functional', () {
     test('constructorTest', () {
       if(AudioContext.supported) {
         var ctx = new AudioContext();
         expect(ctx, isNotNull);
         expect(ctx, isAudioContext);
       }
     });
 
     test('createBuffer', () {
       if(AudioContext.supported) {
         var ctx = new AudioContext();
-        ArrayBufferView arrayBufferView = new Float32Array.fromList([]);
+        Float32List view = new Float32List.fromList([]);
         try {
           // Test that native overload is chosen correctly. Native
           // implementation should throw 'SyntaxError' DomException because the
           // buffer is empty.
-          AudioBuffer buffer = ctx.createBuffer(arrayBufferView.buffer, false);
+          AudioBuffer buffer = ctx.createBuffer(view.buffer, false);
         } catch (e) {
           expect(e.name, DomException.SYNTAX);
         }
       }
     });
 
     test('audioRenames', () {
       if(AudioContext.supported) {
         AudioContext context = new AudioContext();
         GainNode gainNode = context.createGain();
@@ skipping 21 matching lines @@
           if (!alreadyCalled) {
             completer.complete(true);
           }
           alreadyCalled = true;
         });
         return completer.future;
       }
     });
   });
 }