Update PPAPI IDL generator to define versioned structs, and unversioned typedef.

ppapi/proxy/ppb_audio_proxy.h

Index: ppapi/proxy/ppb_audio_proxy.h
diff --git a/ppapi/proxy/ppb_audio_proxy.h b/ppapi/proxy/ppb_audio_proxy.h
index feee8dcd6078aadeb4efd544d083758f0ac50115..0e12bdb95e8a7d12349891660b0bf9e1bb615d59 100644
--- a/ppapi/proxy/ppb_audio_proxy.h
+++ b/ppapi/proxy/ppb_audio_proxy.h
@@ -12,16 +12,12 @@
 #include "base/sync_socket.h"
 #include "ipc/ipc_platform_file.h"
 #include "ppapi/c/pp_instance.h"
-#include "ppapi/c/pp_module.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/ppb_audio.h"
-#include "ppapi/c/ppb_audio_config.h"
 #include "ppapi/cpp/completion_callback.h"
 #include "ppapi/proxy/interface_proxy.h"
 #include "ppapi/proxy/proxy_non_thread_safe_ref_count.h"
 
-struct PPB_Audio;
-
 namespace ppapi {
 
 class HostResource;