Fix the crash for the AudioShared.

ppapi/nacl_irt/plugin_startup.cc

Index: ppapi/nacl_irt/plugin_startup.cc
diff --git a/ppapi/nacl_irt/plugin_startup.cc b/ppapi/nacl_irt/plugin_startup.cc
index 986fe32337087dd76f6a294cdc9c22f4cb627b89..960b90bf674b0ecae5e6c2dd0506081d731f2272 100644
--- a/ppapi/nacl_irt/plugin_startup.cc
+++ b/ppapi/nacl_irt/plugin_startup.cc
@@ -11,6 +11,7 @@
 #include "base/threading/thread.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ppapi/nacl_irt/manifest_service.h"
+#include "ppapi/shared_impl/ppb_audio_shared.h"
 
 namespace ppapi {
 namespace {
@@ -79,6 +80,8 @@ void StartUpPlugin() {
         base::Bind(StartUpManifestServiceOnIOThread, &event));
     event.Wait();
   }
+
+  PPB_Audio_Shared::SetNaClMode(true);
 }
 
 int GetBrowserIPCFileDescriptor() {