AllowBroadcast() is exposed to NaCl.

ppapi/native_client/src/shared/ppapi_proxy/ppb_udp_socket_private.srpc

 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # RPC methods used to implement PPB_UDPSocket_Private calls from the plugin.
 # See ppapi/c/private/ppb_udp_socket_private.h for interface details.
 
 {
   'name': 'PpbUDPSocketPrivateRpc',
   'rpcs': [
     {'name': 'PPB_UDPSocket_Private_Create',
      'inputs': [['instance_id', 'PP_Instance'],        # PP_Instance
                 ],
      'outputs': [['resource', 'PP_Resource'],          # PP_Resource
                  ]
     },
     {'name': 'PPB_UDPSocket_Private_IsUDPSocket',
      'inputs': [['resource_id', 'PP_Resource'],        # PP_Resource
                 ],
      'outputs': [['is_udp_socket_private', 'int32_t'], # PP_Bool
                  ]
     },
+    {'name': 'PPB_UDPSocket_Private_SetSocketFeature',
+     'inputs': [['udp_socket', 'PP_Resource'],         # PP_Resource
+                ['name', 'int32_t'],               # PP_UDPSocketFeature_Private
+                ['value', 'char[]'],                   # PP_Var
+                ],
+     'outputs': [['pp_error', 'int32_t'],
+                ]
+    },
     {'name': 'PPB_UDPSocket_Private_Bind',
      'inputs': [['udp_socket', 'PP_Resource'],         # PP_Resource
                 ['addr', 'char[]'],                    # PP_NetAddress_Private*
                 ['callback_id', 'int32_t'],            # PP_CompletionCallback
                 ],
      'outputs': [['pp_error', 'int32_t'],
                  ]
     },
     {'name': 'PPB_UDPSocket_Private_GetBoundAddress',
      'inputs': [['udp_socket', 'PP_Resource'],         # PP_Resource
@@ skipping 28 matching lines @@
      'outputs': [['pp_error_or_bytes', 'int32_t'],
                  ]
     },
     {'name': 'PPB_UDPSocket_Private_Close',
      'inputs': [['udp_socket', 'PP_Resource'],         # PP_Resource
                 ],
      'outputs': []
     },
    ]
 }