Initial proto for language detection.

components/sync/protocol/user_event_specifics.proto

Index: components/sync/protocol/user_event_specifics.proto
diff --git a/components/sync/protocol/user_event_specifics.proto b/components/sync/protocol/user_event_specifics.proto
index fa74e61191c68b9baa92b54ece3a38c978069253..88f610973614f87f33fc37ba636c05f9bcbb0d28 100644
--- a/components/sync/protocol/user_event_specifics.proto
+++ b/components/sync/protocol/user_event_specifics.proto
@@ -13,6 +13,20 @@ option optimize_for = LITE_RUNTIME;
 
 package sync_pb;
 
+// Language detection output.
+message LanguageDetection {
+  message Language {
+    // ISO 639 language code will be used.
+    optional string language_code = 1;
+    // The detected language proportion score.
+    optional int32 proportion = 2;

[napper, 2017/05/18 06:02:13]

As discussed offline, switch to a bool is_reliable flag.

[renjieliu1, 2017/05/18 06:08:56]

Done.

+  }
+  // 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.
+  repeated Language detected_languages = 1;
+  optional string adopted_language = 2;
+}
+
 message FieldTrialEvent {
   message FieldTrial {
     optional fixed32 name_id = 1;
@@ -32,5 +46,8 @@ message UserEventSpecifics {
   // other events belonged to.
   optional fixed64 session_id = 3;
 
-  oneof event { FieldTrialEvent field_trial_event = 4; }
+  oneof event {
+    FieldTrialEvent field_trial_event = 4;
+    LanguageDetection translate_language_detection = 5;

[napper, 2017/05/18 06:02:13]

Just language_detection

[renjieliu1, 2017/05/18 06:08:56]

Done.

+  }
 }