[translate] Add ranker model proto and loader.

components/translate/core/browser/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/ui.gni")
 
 static_library("browser") {
   sources = [
     "language_model.cc",
     "language_model.h",
     "language_state.cc",
     "language_state.h",
     "page_translated_details.h",
+    "ranker_model.cc",
+    "ranker_model.h",
+    "ranker_model_loader.cc",
+    "ranker_model_loader.h",
     "translate_accept_languages.cc",
     "translate_accept_languages.h",
     "translate_browser_metrics.cc",
     "translate_browser_metrics.h",
     "translate_client.h",
     "translate_download_manager.cc",
     "translate_download_manager.h",
     "translate_driver.h",
     "translate_error_details.h",
     "translate_event_details.cc",
@@ skipping 59 matching lines @@
   }
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "language_model_unittest.cc",
     "language_state_unittest.cc",
     "mock_translate_driver.cc",
     "mock_translate_driver.h",
+    "ranker_model_loader_unittest.cc",
+    "ranker_model_unittest.cc",
     "translate_browser_metrics_unittest.cc",
     "translate_language_list_unittest.cc",
     "translate_manager_unittest.cc",
     "translate_prefs_unittest.cc",
     "translate_ranker_unittest.cc",
     "translate_script_unittest.cc",
     "translate_ui_delegate_unittest.cc",
   ]
   deps = [
     ":browser",
     "//base",
     "//components/infobars/core",
     "//components/metrics/proto",
     "//components/pref_registry:pref_registry",
     "//components/prefs",
     "//components/prefs:test_support",
     "//components/sync_preferences:test_support",
     "//components/translate/core/browser/proto",
     "//components/translate/core/common",
     "//components/variations",
     "//net:test_support",
     "//testing/gtest",
   ]
 }