Add an ONC property for disabling LCP echo

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 3db2cfa80d02845f2072dbdf5c8a03acd994363a..564b9dc3f8340175705cdd9edec76c7e678c4178 100644
--- a/chromeos/network/onc/onc_translation_tables.cc
+++ b/chromeos/network/onc/onc_translation_tables.cc
@@ -54,11 +54,12 @@ const FieldTranslationEntry xauth_fields[] = {
     {NULL}};
 
 const FieldTranslationEntry l2tp_fields[] = {
-    {::onc::vpn::kPassword, shill::kL2tpIpsecPasswordProperty},
+    {::onc::l2tp::kPassword, shill::kL2tpIpsecPasswordProperty},
     // We don't synchronize l2tp's SaveCredentials field for now, as Shill
     // doesn't support separate settings for ipsec and l2tp.
-    // { ::onc::vpn::kSaveCredentials, &kBoolSignature },
-    {::onc::vpn::kUsername, shill::kL2tpIpsecUserProperty},
+    // { ::onc::l2tp::kSaveCredentials, &kBoolSignature },
+    {::onc::l2tp::kUsername, shill::kL2tpIpsecUserProperty},
+    {::onc::l2tp::kLcpEchoDisabled, shill::kL2tpIpsecLcpEchoDisabledProperty},

[pneubeck (no reviews), 2015/04/07 09:45:20]

please add documentation for this field to  components/onc/docs/onc_spec.html

I didn't find any documentation for this field in Shill.

[Paul Stewart, 2015/04/07 15:34:33]

It's a little late for this CL.  See https://codereview.chromium.org/1060333003

     {NULL}};
 
 const FieldTranslationEntry openvpn_fields[] = {