[NaCl SDK] Add some more logging to nacl_io.

native_client_sdk/src/libraries/nacl_io/socket/udp_node.cc

Index: native_client_sdk/src/libraries/nacl_io/socket/udp_node.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/socket/udp_node.cc b/native_client_sdk/src/libraries/nacl_io/socket/udp_node.cc
index 582286d538e1016732ab272843256047a72f706b..816f8e9a832498ed78f2b312af2617c6d0e6f8b6 100644
--- a/native_client_sdk/src/libraries/nacl_io/socket/udp_node.cc
+++ b/native_client_sdk/src/libraries/nacl_io/socket/udp_node.cc
@@ -9,6 +9,7 @@
 
 #include <algorithm>
 
+#include "nacl_io/log.h"
 #include "nacl_io/pepper_interface.h"
 #include "nacl_io/socket/packet.h"
 #include "nacl_io/socket/udp_event_emitter.h"
@@ -169,13 +170,17 @@ Error UdpNode::Init(int open_flags) {
   if (err != 0)
     return err;
 
-  if (UDPInterface() == NULL)
+  if (UDPInterface() == NULL) {
+    LOG_ERROR("Got NULL interface: UDP");
     return EACCES;
+  }
 
   socket_resource_ =
       UDPInterface()->Create(filesystem_->ppapi()->GetInstance());
-  if (0 == socket_resource_)
+  if (0 == socket_resource_) {
+    LOG_ERROR("Unable to create UDP resource.");
     return EACCES;
+  }
 
   return 0;
 }