Reland 95309. Add a template to handle properly issuing completion callbacks.

ppapi/thunk/ppb_audio_api.h

 // Copyright (c) 2011 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_THUNK_AUDIO_API_H_
 #define PPAPI_THUNK_AUDIO_API_H_
 
+#include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/ppb_audio.h"
 
 namespace ppapi {
 namespace thunk {
 
 class PPB_Audio_API {
  public:
   virtual ~PPB_Audio_API() {}
 
   virtual PP_Resource GetCurrentConfig() = 0;
   virtual PP_Bool StartPlayback() = 0;
   virtual PP_Bool StopPlayback() = 0;
+
+  // Trusted API.
+  virtual int32_t OpenTrusted(PP_Resource config_id,
+                              PP_CompletionCallback create_callback) = 0;
+  virtual int32_t GetSyncSocket(int* sync_socket) = 0;
+  virtual int32_t GetSharedMemory(int* shm_handle, uint32_t* shm_size) = 0;
 };
 
 }  // namespace thunk
 }  // namespace ppapi
 
 #endif  // PPAPI_THUNK_AUDIO_API_H_