Initial translation event proto.

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 21 matching lines @@
   }
   // 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.
   // It will be stored only if it's different from the first detected language.
   optional string adopted_language = 2;
 }
 
+// User translated a page or interacted with translate suggestion.
+message Translation {
+  optional string from_language_code = 1;

[amoylan, 2017/05/26 05:12:42]

We need a comment on these fields (from_language_code, to_language_code).
Actually I think we need a somewhat detailed comment  here, because I feel like
they can have a different meaning (or no meaning) depending on the value of
Interaction enum.

For example, if interaction == MANUAL, will the from_ and to_ be the previous
auto-chosen values? Or the updated values? Or maybe exactly one of the from_ and
to_ will be set, indicating which one the user did manually enter?

[renjieliu1, 2017/05/29 00:09:50]

Done.

+  optional string to_language_code = 2;
+  enum Interaction {
+    UNKNOWN = 0;
+    ACCEPTED = 1;
+    REJECTED = 2;
+    IGNORED = 3;
+    DISMISSED = 4;
+    MANUAL = 5;  // User manually entered either language.
+    ALWAYS_TRANSLATE = 6;
+    NEVER_TRANSLATE = 7;
+  }
+  optional Interaction interaction = 3;
+}
+
 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;
+    Translation translation = 6;
   }
 }