Support configuring number of audio buffers in MediaStream Pepper API.

ppapi/proxy/ppapi_messages.h

Index: ppapi/proxy/ppapi_messages.h
diff --git a/ppapi/proxy/ppapi_messages.h b/ppapi/proxy/ppapi_messages.h
index 95ac3d9e0d89c37bd1462bcc2447187b681efd34..7a39c227f6c02e3f007ba55c93c3365fb60be6f6 100644
--- a/ppapi/proxy/ppapi_messages.h
+++ b/ppapi/proxy/ppapi_messages.h
@@ -61,6 +61,7 @@
 #include "ppapi/shared_impl/file_growth.h"
 #include "ppapi/shared_impl/file_path.h"
 #include "ppapi/shared_impl/file_ref_create_info.h"
+#include "ppapi/shared_impl/media_stream_audio_track_shared.h"
 #include "ppapi/shared_impl/media_stream_video_track_shared.h"
 #include "ppapi/shared_impl/ppapi_nacl_plugin_args.h"
 #include "ppapi/shared_impl/ppapi_preferences.h"
@@ -240,6 +241,10 @@ IPC_STRUCT_TRAITS_BEGIN(ppapi::FlashSiteSetting)
   IPC_STRUCT_TRAITS_MEMBER(permission)
 IPC_STRUCT_TRAITS_END()
 
+IPC_STRUCT_TRAITS_BEGIN(ppapi::MediaStreamAudioTrackShared::Attributes)
+  IPC_STRUCT_TRAITS_MEMBER(buffers)
+IPC_STRUCT_TRAITS_END()
+
 IPC_STRUCT_TRAITS_BEGIN(ppapi::MediaStreamVideoTrackShared::Attributes)
   IPC_STRUCT_TRAITS_MEMBER(buffers)
   IPC_STRUCT_TRAITS_MEMBER(width)
@@ -1436,6 +1441,10 @@ IPC_MESSAGE_CONTROL1(PpapiPluginMsg_IsolatedFileSystem_BrowserOpenReply,
 // MediaStream -----------------------------------------------------------------
 IPC_MESSAGE_CONTROL1(PpapiPluginMsg_MediaStreamAudioTrack_CreateFromPendingHost,
                      std::string /* track_id */)
+IPC_MESSAGE_CONTROL1(
+    PpapiHostMsg_MediaStreamAudioTrack_Configure,
+    ppapi::MediaStreamAudioTrackShared::Attributes /* attributes */)
+IPC_MESSAGE_CONTROL0(PpapiPluginMsg_MediaStreamAudioTrack_ConfigureReply)
 IPC_MESSAGE_CONTROL1(PpapiPluginMsg_MediaStreamVideoTrack_CreateFromPendingHost,
                      std::string /* track_id */)
 IPC_MESSAGE_CONTROL0(PpapiHostMsg_MediaStreamVideoTrack_Create)