AllowBroadcast() is exposed to NaCl.

ppapi/shared_impl/private/udp_socket_private_impl.h

Index: ppapi/shared_impl/private/udp_socket_private_impl.h
diff --git a/ppapi/shared_impl/private/udp_socket_private_impl.h b/ppapi/shared_impl/private/udp_socket_private_impl.h
index 36d51ca0e94b45ac4ea38ba305ba1e4f773451fe..16c6939073708ed382d9e2103d56a6f1d4747e33 100644
--- a/ppapi/shared_impl/private/udp_socket_private_impl.h
+++ b/ppapi/shared_impl/private/udp_socket_private_impl.h
@@ -40,6 +40,10 @@ class PPAPI_SHARED_EXPORT UDPSocketPrivateImpl
   virtual PPB_UDPSocket_Private_API* AsPPB_UDPSocket_Private_API() OVERRIDE;
 
   // PPB_UDPSocket_Private_API implementation.
+  virtual int32_t SetSocketFeature(
+      PP_UDPSocketFeature_Private name,
+      PP_Var value,
+      scoped_refptr<TrackedCallback> callback) OVERRIDE;
   virtual int32_t Bind(const PP_NetAddress_Private* addr,
                        scoped_refptr<TrackedCallback> callback) OVERRIDE;
   virtual PP_Bool GetBoundAddress(PP_NetAddress_Private* addr) OVERRIDE;
@@ -54,6 +58,7 @@ class PPAPI_SHARED_EXPORT UDPSocketPrivateImpl
   virtual void Close() OVERRIDE;
 
   // Notifications from the proxy.
+  void OnSetSocketFeatureCompleted(bool succeeded);
   void OnBindCompleted(bool succeeded,
                        const PP_NetAddress_Private& bound_addr);
   void OnRecvFromCompleted(bool succeeded,
@@ -63,6 +68,8 @@ class PPAPI_SHARED_EXPORT UDPSocketPrivateImpl
 
   // Send functions that need to be implemented differently for
   // the proxied and non-proxied derived classes.
+  virtual void SendSetSocketFeature(PP_UDPSocketFeature_Private name,
+                                    PP_Var value) = 0;
   virtual void SendBind(const PP_NetAddress_Private& addr) = 0;
   virtual void SendRecvFrom(int32_t num_bytes) = 0;
   virtual void SendSendTo(const std::string& buffer,
@@ -78,6 +85,7 @@ class PPAPI_SHARED_EXPORT UDPSocketPrivateImpl
   bool bound_;
   bool closed_;
 
+  scoped_refptr<TrackedCallback> setsocketfeature_callback_;
   scoped_refptr<TrackedCallback> bind_callback_;
   scoped_refptr<TrackedCallback> recvfrom_callback_;
   scoped_refptr<TrackedCallback> sendto_callback_;