Fix the crash for the AudioShared.

ppapi/shared_impl/ppb_audio_shared.h

Index: ppapi/shared_impl/ppb_audio_shared.h
diff --git a/ppapi/shared_impl/ppb_audio_shared.h b/ppapi/shared_impl/ppb_audio_shared.h
index b503c534649cd1ee886dba922fdc68b54d600065..2fc48a15e97a7bec118cc2f7b6efd4dc5008fffb 100644
--- a/ppapi/shared_impl/ppb_audio_shared.h
+++ b/ppapi/shared_impl/ppb_audio_shared.h
@@ -15,9 +15,7 @@
 #include "ppapi/shared_impl/resource.h"
 #include "ppapi/thunk/ppb_audio_api.h"
 
-#if defined(OS_NACL)
-#include "ppapi/nacl_irt/irt_ppapi.h"
-#endif
+struct PP_ThreadFunctions;
 
 namespace ppapi {
 
@@ -79,11 +77,9 @@ class PPAPI_SHARED_EXPORT PPB_Audio_Shared
                      PP_AudioSampleRate sample_rate,
                      int sample_frame_count);
 
-#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.
@@ -113,12 +109,11 @@ class PPAPI_SHARED_EXPORT PPB_Audio_Shared
 #if !defined(OS_NACL)
   // When the callback is set, this thread is spawned for calling it.
   scoped_ptr<base::DelegateSimpleThread> audio_thread_;
-#else
+#endif
   uintptr_t thread_id_;
   bool thread_active_;
 
   static void CallRun(void* self);
-#endif
 
   // Callback to call when audio is ready to accept new samples.
   AudioCallbackCombined callback_;