Add first part of the network_tester functionality.

webrtc/tools/network_tester/config_reader.h

+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_TOOLS_NETWORK_TESTER_CONFIG_READER_H_
+#define WEBRTC_TOOLS_NETWORK_TESTER_CONFIG_READER_H_
+
+#include <fstream>
+#include <string>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/optional.h"
+
+namespace webrtc {
+
+class ConfigReader {
+ public:
+  struct Config {
+    int packet_send_interval_ms;
+    int packet_size;
+    int execution_time_ms;
+  };
+  explicit ConfigReader(const std::string& config_file_path);
+  ~ConfigReader();
+
+  rtc::Optional<Config> GetNextConfig();
+  std::ifstream config_stream_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(ConfigReader);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_TOOLS_NETWORK_TESTER_CONFIG_READER_H_