Add an ONC property for setting per-network roam threshold

chromeos/network/onc/onc_translation_tables.cc

Index: chromeos/network/onc/onc_translation_tables.cc
diff --git a/chromeos/network/onc/onc_translation_tables.cc b/chromeos/network/onc/onc_translation_tables.cc
index 564b9dc3f8340175705cdd9edec76c7e678c4178..f8bd487dccf7d304f981b6804bef48f318d5e5b6 100644
--- a/chromeos/network/onc/onc_translation_tables.cc
+++ b/chromeos/network/onc/onc_translation_tables.cc
@@ -120,6 +120,7 @@ const FieldTranslationEntry wifi_fields[] = {
     {::onc::wifi::kHexSSID, shill::kWifiHexSsid},
     {::onc::wifi::kHiddenSSID, shill::kWifiHiddenSsid},
     {::onc::wifi::kPassphrase, shill::kPassphraseProperty},
+    {::onc::wifi::kRoamThreshold, shill::kWifiRoamThresholdProperty},
     // This field is converted during translation, see onc_translator_*.
     // { ::onc::wifi::kSecurity, shill::kSecurityClassProperty },
     {::onc::wifi::kSignalStrength, shill::kSignalStrengthProperty},