Add test to make sure if PPB_Audio_Shared::StartThread() works.

ppapi/shared_impl/ppb_audio_shared.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 PPAPI_SHARED_IMPL_PPB_AUDIO_SHARED_H_
 #define PPAPI_SHARED_IMPL_PPB_AUDIO_SHARED_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "base/sync_socket.h"
@@ skipping 61 matching lines @@
 
   // Sets the shared memory and socket handles. This will automatically start
   // playback if we're currently set to play.
   void SetStreamInfo(PP_Instance instance,
                      base::SharedMemoryHandle shared_memory_handle,
                      size_t shared_memory_size,
                      base::SyncSocket::Handle socket_handle,
                      PP_AudioSampleRate sample_rate,
                      int sample_frame_count);
 
+  // Returns whether a thread can be created on the client context.
+  // In trusted plugin, this should always return true, as it uses Chrome's
+  // thread library. In NaCl plugin, this returns whether SetThreadFunctions
+  // was invoked properly.
+  static bool IsThreadFunctionReady();
+
 #if defined(OS_NACL)
   // NaCl has a special API for IRT code to create threads that can call back
   // into user code.
   static void SetThreadFunctions(const struct PP_ThreadFunctions* functions);
 #endif
 
  private:
   // Starts execution of the audio thread.
   void StartThread();
 
@@ skipping 46 matching lines @@
 
   // Buffer index used to coordinate with the browser side audio receiver.
   uint32_t buffer_index_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_Audio_Shared);
 };
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_PPB_AUDIO_SHARED_H_