Return from |Configure()| asynchronously, and allow |InitBuffers()| to return errors.

ppapi/tests/test_media_stream_audio_track.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_TESTS_TEST_MEDIA_STREAM_AUDIO_TRACK_H_
 #define PPAPI_TESTS_TEST_MEDIA_STREAM_AUDIO_TRACK_H_
 
 #include <string>
 
 #include "ppapi/cpp/media_stream_audio_track.h"
@@ skipping 13 matching lines @@
   // Overrides.
   virtual void HandleMessage(const pp::Var& message_data);
 
   // Test helpers.
   std::string CheckConfigure(int32_t attrib_list[], int32_t expected_result);
   std::string CheckGetBuffer(int times, int expected_duration);
 
   std::string TestCreate();
   std::string TestGetBuffer();
   std::string TestConfigure();
+  std::string TestConfigureClose();
 
   pp::MediaStreamAudioTrack audio_track_;
 
   NestedEvent event_;
 };
 
 #endif  // PPAPI_TESTS_TEST_MEDIA_STREAM_AUDIO_TRACK_H_