Use GUID instead of ServicePath in networkingPrivate API

chromeos/network/network_state.cc

Index: chromeos/network/network_state.cc
diff --git a/chromeos/network/network_state.cc b/chromeos/network/network_state.cc
index f473fcdadcd74a01e4d0e78d0d5e0ede38e65b2e..a50c7d59fe8ec356874bbf34ef43eb26951220b9 100644
--- a/chromeos/network/network_state.cc
+++ b/chromeos/network/network_state.cc
@@ -252,6 +252,10 @@ std::string NetworkState::GetNetmask() const {
   return network_util::PrefixLengthToNetmask(prefix_length_);
 }
 
+void NetworkState::SetGuid(const std::string& guid) {
+  guid_ = guid;
+}
+
 bool NetworkState::UpdateName(const base::DictionaryValue& properties) {
   std::string updated_name =
       shill_property_util::GetNameFromProperties(path(), properties);