Add a new parameter |latency| to PPB_Audio.

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 fa887de7f1a0000e5b001d050ecbd9132bbd934f..a8c683d88a1ea7aff5d1be531e456d972ddc4ace 100644
--- a/ppapi/proxy/ppb_audio_proxy.h
+++ b/ppapi/proxy/ppb_audio_proxy.h
@@ -21,6 +21,7 @@
 
 namespace ppapi {
 
+class AudioCallback;
 class HostResource;
 
 namespace proxy {
@@ -33,11 +34,11 @@ class PPB_Audio_Proxy : public InterfaceProxy {
   virtual ~PPB_Audio_Proxy();
 
   // Creates an Audio object in the plugin process.
-  static PP_Resource CreateProxyResource(PP_Instance instance_id,
-                                         PP_Resource config_id,
-                                         PPB_Audio_Callback audio_callback,
-                                         void* user_data);
-
+  static PP_Resource CreateProxyResource(
+      PP_Instance instance_id,
+      PP_Resource config_id,
+      const AudioCallback& audio_callback,
+      void* user_data);
 
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);