Move generic model directly in the RankerModelProto.

Deleting CS Ranker Model. This change is not wire-compatible, but we have not published any CS models yet. So, this should not break anything.

Bug: 759161
Change-Id: I43e6a2885a97ab030eb43edd01e44773e6239693
Reviewed-on: https://chromium-review.googlesource.com/732167Reviewed-by: Roger McFarlane <rogerm@chromium.org>
Commit-Queue: Philippe Hamel <hamelphi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513250}

components/machine_intelligence/proto/BUILD.gn

@@ -6,7 +6,6 @@ import("//third_party/protobuf/proto_library.gni")
 
 proto_library("proto") {
   sources = [
-    "contextual_search_ranker_model.proto",
     "generic_logistic_regression_model.proto",
     "ranker_example.proto",
     "ranker_model.proto",

components/machine_intelligence/proto/contextual_search_ranker_model.proto

-// Copyright (c) 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.
-//
-// Assist Model for Contextual Search.
-
-syntax = "proto2";
-
-option optimize_for = LITE_RUNTIME;
-
-import "generic_logistic_regression_model.proto";
-
-package machine_intelligence;
-
-// Defines a Contextual Search Ranker Model.
-message ContextualSearchRankerModel {
-  // A number that identifies the version of this model.
-  optional uint32 version = 1;
-
-  oneof model_revision {
-    GenericLogisticRegressionModel generic_logistic_regression_model = 2;
-  }
-}
\ No newline at end of file

components/machine_intelligence/proto/ranker_model.proto

@@ -9,14 +9,14 @@ syntax = "proto2";
 option optimize_for = LITE_RUNTIME;
 
 import "translate_ranker_model.proto";
-import "contextual_search_ranker_model.proto";
+import "generic_logistic_regression_model.proto";
 
 package machine_intelligence;
 
 // Metadata for a ranker model instance. This data describes how the ranker
 // model should be interpreted/used.
 message RankerModelMetadata {
-  // An identifier denoting the type or purpose of this model.
+  // An identifier denoting the type or purpose of this model. E.g. "Translate".
   optional string name = 1;
 
   // An identifier denoting the specific instance of this model. For example:
@@ -39,6 +39,9 @@ message RankerModelMetadata {
   // instance of the model never expires. A new download can be triggered by
   // changing the configured source URL for the model loader.
   optional int64 cache_duration_sec = 5;
+
+  // The version of the model. E.g. 20171027.
+  optional uint32 model_version = 6;
 }
 
 // Defines an envelope/wrapper for general models.
@@ -48,6 +51,6 @@ message RankerModelProto {
 
   oneof model {
     TranslateRankerModel translate = 2;
-    ContextualSearchRankerModel contextual_search = 3;
+    GenericLogisticRegressionModel logistic_regression = 3;
   }
 }