added abstract optimizer class.

modules/planning/optimizer/BUILD

+package(default_visibility = ["//visibility:public"])
+
+cc_library(
+    name = "optimizer",
+    srcs = [
+        "optimizer.cc",
+    ],
+    hdrs = [
+        "optimizer.h",
+    ],
+    deps = [
+        "//modules/common/proto:error_code_proto",
+    ],
+)

modules/planning/optimizer/optimizer.cc

+/******************************************************************************
+ * Copyright 2017 The Apollo Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *****************************************************************************/
+
+/**
+ * @file optimizer.cc
+ **/
+
+#include "modules/planning/optimizer/optimizer.h"
+
+namespace apollo {
+namespace planning {
+
+Optimizer::Optimizer(const std::string& name) : _name(name) {}
+
+const std::string& Optimizer::name() const { return _name; }
+
+}  // namespace planning
+}  // namespace apollo

modules/planning/optimizer/optimizer.h

+/******************************************************************************
+ * Copyright 2017 The Apollo Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *****************************************************************************/
+
+/**
+ * @file optimizer.h
+ **/
+
+#ifndef MODULES_PLANNING_OPTIMIZER_OPTIMIZER_H_
+#define MODULES_PLANNING_OPTIMIZER_OPTIMIZER_H_
+
+#include <string>
+
+#include "modules/common/proto/error_code.pb.h"
+
+namespace apollo {
+namespace planning {
+
+class Optimizer {
+ public:
+  explicit Optimizer(const std::string& name);
+  virtual ~Optimizer() = default;
+  virtual const std::string& name() const;
+
+ private:
+  const std::string _name;
+};
+
+}  // namespace planning
+}  // namespace apollo
+
+#endif  // MODULES_PLANNING_OPTIMIZER_OPTIMIZER_H_