Move ranker_model_loader to a new component.

components/translate/core/browser/proto/translate_ranker_model.proto

-// Copyright (c) 2016 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.
-//
-// Experimental Translation Assist Model to allow/suppress translation prompts.
-
-syntax = "proto2";
-
-option optimize_for = LITE_RUNTIME;
-
-package chrome_intelligence;
-
-// Defines a Chrome Ranker Translate Model.
-// Next tag: 13
-message TranslateRankerModel {
-  // A number that identifies the version of this model.
-  optional uint32 version = 1;
-
-  // Defines the weights and bias of a Logistic Regression Model.
-  message LogisticRegressionModel {
-    // Decision threshold. If not defined, use 0.5.
-    optional float threshold = 12;
-
-    optional float bias = 1;
-
-    optional float accept_ratio_weight = 2;
-    optional float decline_ratio_weight = 3;
-    optional float ignore_ratio_weight = 4;
-
-    optional float accept_count_weight = 9;
-    optional float decline_count_weight = 10;
-    optional float ignore_count_weight = 11;
-
-    // One-hot features are encoded in the form of a map. These maps
-    // each contain an element 'UNKNOWN' to use in case the key is not
-    // found in the map.
-    map<string, float> source_language_weight = 5;
-    map<string, float> target_language_weight = 6;
-    map<string, float> country_weight = 7;
-    map<string, float> locale_weight = 8;
-  }
-
-  oneof model_revision {
-    LogisticRegressionModel logistic_regression_model = 2;
-  }
-}