Implement client side logging for language detection.

components/sync/protocol/user_event_specifics.proto

 // Copyright 2017 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 user events.
 
 // Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
 // any fields in this file.
 
 syntax = "proto2";
@@ skipping 16 matching lines @@
     // ISO 639 language code will be used.
     optional string language_code = 1;
     // Whether the detected language is reliable, note this is determined by
     // the CLD3.
     optional bool is_reliable = 2;
   }
   // Top n languages. Typically we just log the top language, but for page that
   // we're not confident about, we may log up to 3 top languages in descending
   // order.
   repeated Language detected_languages = 1;
-  // Adopted language is the final determined language.
+  // Adopted language code is the code of final determined language.
   // It will be stored only if it's different from the first detected language.
-  optional string adopted_language = 2;
+  optional string adopted_language_code = 2;
 }
 
 message UserEventSpecifics {
   // Time of event, as measured on the client (unix epoch).
   optional int64 event_time_usec = 1;
 
   // The |global_id| field of the associated navigation, if there is one.
   optional int64 navigation_id = 2;
 
   // On startup we generate a new random id to identify which FieldTrialEvents
   // other events belonged to.
   optional fixed64 session_id = 3;
 
   oneof event {
     FieldTrialEvent field_trial_event = 4;
     LanguageDetection language_detection = 5;
   }
 }