Add first part of the network_tester functionality.

webrtc/tools/network_tester/packet_sender.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_PACKET_SENDER_H_
+#define WEBRTC_TOOLS_NETWORK_TESTER_PACKET_SENDER_H_
+
+#include <memory>
+#include <string>
+
+#include "webrtc/base/ignore_wundef.h"
+#include "webrtc/base/task_queue.h"
+
+#ifdef WEBRTC_NETWORK_TESTER_PROTO
+RTC_PUSH_IGNORING_WUNDEF()
+#include "webrtc/tools/network_tester/network_tester_packet.pb.h"
+RTC_POP_IGNORING_WUNDEF()
+using webrtc::network_tester::packet::NetworkTesterPacket;
+#else
+class NetworkTesterPacket;
+#endif  // WEBRTC_NETWORK_TESTER_PROTO
+
+namespace webrtc {
+
+class TestController;
+
+class PacketSender {
+ public:
+  PacketSender(TestController* test_controller,
+               const std::string& config_file_path);
+  ~PacketSender();
+
+  void StartSending();
+  void StopSending();
+  bool IsSending() const;
+
+  void SendPacket();
+
+  int64_t GetSendIntervalMs() const;
+  void UpdateTestSetting(size_t packet_size, int64_t send_interval_ms);
+
+ private:
+  rtc::TaskQueue worker_queue_;

[stefan-webrtc, 2017/04/05 07:46:53]

Perhaps also use a SeqeuenceChecker to document where things are called?

[michaelt, 2017/04/05 10:15:31]

Done.

+  size_t packet_size_;
+  int64_t send_interval_ms_;
+  int64_t sequence_number_;
+  bool sending_;
+  const std::string config_file_path_;
+  TestController* const test_controller_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(PacketSender);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_TOOLS_NETWORK_TESTER_PACKET_SENDER_H_