Supplimentary identifier for passwords specific

components/sync/protocol/password_specifics.proto

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Sync protocol datatype extension for password data.
 
 // Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
 // any fields in this file.
 
 syntax = "proto2";
@@ skipping 92 matching lines @@
 
   // A URL of the avatar for the credential. Set by CredentialManager API and
   // Android.
   optional string avatar_url = 16;
 
   // A URL of the IdP used to verify the credential. Set by Credential Manager
   // API and Android.
   optional string federation_url = 17;
 }
 
+// Contains the password specifics metadata which simplifies its lookup.
+message PasswordSpecificsMetadata {
+  optional string url = 1;
+};
+
 // Properties of password sync objects.
 message PasswordSpecifics {
   // The actual password data. Contains an encrypted PasswordSpecificsData
   // message.
   optional EncryptedData encrypted = 1;
   // An unsynced field for use internally on the client. This field should
   // never be set in any network-based communications.
   optional PasswordSpecificsData client_only_encrypted_data = 2;
+  // Password related metadata, which is sent to the server side. The field
+  // should never be set for full encryption and data is the explicitly cleared

[Nicolas Zea, 2016/08/20 00:23:43]

nit: the last sentence is a bit tough to parse. How about:
"The field should never be set for full encryption users. If encryption is
enabled, this field must be cleared".

+  // out and no longer sent to the server.
+  optional PasswordSpecificsMetadata unencrypted_metadata = 3;

[Nicolas Zea, 2016/08/20 00:23:43]

Note that this also needs to be added to proto_value_conversions.cc (which will
help with debugging)

 }