[translate] Add translate ranker model loader.

components/translate/core/browser/ranker_model.h

+// Copyright 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.
+
+#ifndef COMPONENTS_TRANSLATE_CORE_BROWSER_RANKER_MODEL_H_
+#define COMPONENTS_TRANSLATE_CORE_BROWSER_RANKER_MODEL_H_
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+
+namespace chrome_intelligence {
+
+class RankerModelProto;
+
+// Wrapper class for chrome_intelligence::TranslateRankerProto.
+class RankerModel {
+ public:
+  RankerModel();
+  ~RankerModel();
+
+  // Returns a new ranker model constructed from |data|.
+  static std::unique_ptr<RankerModel> FromString(const std::string& data);
+
+  const RankerModelProto& proto() const { return *proto_; }
+  RankerModelProto* mutable_proto() const { return proto_.get(); }
+
+  // Returns true if this ranker model has expired.
+  bool IsExpired() const;
+
+  const std::string& GetSourceURL() const;
+
+  // Returns a serialization of this ranker model.
+  std::string SerializeAsString() const;
+
+ private:
+  // The underlying ranker model proto.
+  std::unique_ptr<RankerModelProto> proto_;
+
+  DISALLOW_COPY_AND_ASSIGN(RankerModel);
+};
+
+}  // namesapce chrome_intelligence
+
+#endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_RANKER_MODEL_H_