Updates language model on iOS.

ios/chrome/browser/translate/language_model_factory.h

+// 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.
+
+#ifndef IOS_CHROME_BROWSER_TRANSLATE_LANGUAGE_MODEL_FACTORY_H
+#define IOS_CHROME_BROWSER_TRANSLATE_LANGUAGE_MODEL_FACTORY_H
+
+#include <memory>
+
+#include "base/memory/singleton.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
+
+namespace ios {
+class ChromeBrowserState;
+}
+
+namespace translate {
+class LanguageModel;
+}
+
+class LanguageModelFactory : public BrowserStateKeyedServiceFactory {
+ public:
+  static LanguageModelFactory* GetInstance();
+  static translate::LanguageModel* GetForBrowserState(
+      ios::ChromeBrowserState* browser_state);
+
+ private:
+  friend struct base::DefaultSingletonTraits<LanguageModelFactory>;
+
+  LanguageModelFactory();
+  ~LanguageModelFactory() override;
+
+  // BrowserStateKeyedServiceFactory implementation.
+  std::unique_ptr<KeyedService> BuildServiceInstanceFor(
+      web::BrowserState* context) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(LanguageModelFactory);
+};
+
+#endif  // IOS_CHROME_BROWSER_TRANSLATE_LANGUAGE_MODEL_FACTORY_H