Add first part of the network_tester functionality.

BUG=webrtc:7426

Review-Url: https://codereview.webrtc.org/2779233002
Cr-Commit-Position: refs/heads/master@{#17635}
diff --git a/webrtc/tools/network_tester/test_controller.h b/webrtc/tools/network_tester/test_controller.h
new file mode 100644
index 0000000..5dae3ea
--- /dev/null
+++ b/webrtc/tools/network_tester/test_controller.h
@@ -0,0 +1,75 @@
+/*
+ *  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_TEST_CONTROLLER_H_
+#define WEBRTC_TOOLS_NETWORK_TESTER_TEST_CONTROLLER_H_
+
+#include <array>
+#include <limits>
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "webrtc/base/ignore_wundef.h"
+#include "webrtc/p2p/base/basicpacketsocketfactory.h"
+#include "webrtc/p2p/base/udptransport.h"
+#include "webrtc/tools/network_tester/packet_sender.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 {
+
+constexpr size_t kEthernetMtu = 1500;
+
+class TestController : public sigslot::has_slots<> {
+ public:
+  TestController(int min_port,
+                 int max_port,
+                 const std::string& config_file_path);
+
+  void Run();
+
+  void SendConnectTo(const std::string& hostname, int port);
+
+  void SendData(const NetworkTesterPacket& packet,
+                rtc::Optional<size_t> data_size);
+
+  void OnTestDone();
+
+  bool IsTestDone();
+
+ private:
+  void OnReadPacket(rtc::AsyncPacketSocket* socket,
+                    const char* data,
+                    size_t len,
+                    const rtc::SocketAddress& remote_addr,
+                    const rtc::PacketTime& packet_time);
+  rtc::ThreadChecker test_controller_thread_checker_;
+  rtc::SequencedTaskChecker packet_sender_checker_;
+  rtc::BasicPacketSocketFactory socket_factory_;
+  const std::string config_file_path_;
+  rtc::CriticalSection local_test_done_lock_;
+  bool local_test_done_ GUARDED_BY(local_test_done_lock_);
+  bool remote_test_done_;
+  std::array<char, kEthernetMtu> send_data_;
+  std::unique_ptr<cricket::UdpTransport> udp_transport_;
+  std::unique_ptr<PacketSender> packet_sender_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_TOOLS_NETWORK_TESTER_TEST_CONTROLLER_H_