Add SetProperty() in the PPB_Transport_Dev interface.

ppapi/cpp/dev/transport_dev.cc

Index: ppapi/cpp/dev/transport_dev.cc
diff --git a/ppapi/cpp/dev/transport_dev.cc b/ppapi/cpp/dev/transport_dev.cc
index b625a7d7c02645b118b0b2ec765efdd16965b1fb..7586486fecd990525ccdb4980050adea3f356f88 100644
--- a/ppapi/cpp/dev/transport_dev.cc
+++ b/ppapi/cpp/dev/transport_dev.cc
@@ -36,6 +36,13 @@ bool Transport_Dev::IsWritable() {
       get_interface<PPB_Transport_Dev>()->IsWritable(pp_resource()));
 }
 
+int32_t Transport_Dev::SetConfig(const char* config) {
+  if (!has_interface<PPB_Transport_Dev>())
+    return PP_ERROR_NOINTERFACE;
+  return get_interface<PPB_Transport_Dev>()->SetConfig(
+      pp_resource(), config);
+}
+
 int32_t Transport_Dev::Connect(const CompletionCallback& cc) {
   if (!has_interface<PPB_Transport_Dev>())
     return cc.MayForce(PP_ERROR_NOINTERFACE);