Fix back-to-back StartPlayback/StopPlayback issue in PPAPI IPC proxy

ppapi/tests/test_audio.h

 // Copyright (c) 2012 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 PAPPI_TESTS_TEST_AUDIO_H_
 #define PAPPI_TESTS_TEST_AUDIO_H_
 
 #include <string>
 
 #include "ppapi/c/ppb_audio.h"
 #include "ppapi/c/ppb_audio_config.h"
 #include "ppapi/c/ppb_core.h"
 #include "ppapi/tests/test_case.h"
 
 class TestAudio : public TestCase {
  public:
   explicit TestAudio(TestingInstance* instance);
   ~TestAudio();
 
   // TestCase implementation.
   virtual bool Init();
   virtual void RunTests(const std::string& filter);
 
  private:
   std::string TestCreation();
   std::string TestDestroyNoStop();
   std::string TestFailures();
   std::string TestAudioCallback1();
   std::string TestAudioCallback2();
+  std::string TestAudioCallback3();
 
   // Calls |audio_callback_method_| (where |user_data| is "this").
   static void AudioCallbackTrampoline(void* sample_buffer,
                                       uint32_t buffer_size_in_bytes,
                                       void* user_data);
 
   typedef void (TestAudio::*AudioCallbackMethod)(void* sample_buffer,
                                                  uint32_t buffer_size_in_bytes);
 
   // Method called by |AudioCallbackTrampoline()|. Set only when the callback
@@ skipping 13 matching lines @@
   bool test_done_;
   bool callback_fired_;
 
   // Raw C-level interfaces, set in |Init()|; do not modify them elsewhere.
   const PPB_Audio* audio_interface_;
   const PPB_AudioConfig* audio_config_interface_;
   const PPB_Core* core_interface_;
 };
 
 #endif  // PAPPI_TESTS_TEST_AUDIO_H_