Merges ControlHandler and PacerController.

This is part of a series of CLs preparing to remove
SendSideCongestionController as a separate class.

Bug: webrtc:9586
Change-Id: I0dabd00793e7b436a679d2ef695d2e557a35ae87
Reviewed-on: https://webrtc-review.googlesource.com/c/105420
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25178}

modules/congestion_controller/rtp/control_handler.h

@@ -0,0 +1,71 @@
+/*
+ *  Copyright (c) 2018 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 MODULES_CONGESTION_CONTROLLER_RTP_CONTROL_HANDLER_H_
+#define MODULES_CONGESTION_CONTROLLER_RTP_CONTROL_HANDLER_H_
+
+#include <algorithm>
+#include <memory>
+
+#include "api/transport/network_control.h"
+#include "modules/congestion_controller/include/network_changed_observer.h"
+#include "modules/pacing/paced_sender.h"
+#include "rtc_base/sequenced_task_checker.h"
+
+namespace webrtc {
+// This is used to observe the network controller state and route calls to
+// the proper handler. It also keeps cached values for safe asynchronous use.
+// This makes sure that things running on the worker queue can't access state
+// in SendSideCongestionController, which would risk causing data race on
+// destruction unless members are properly ordered.
+class CongestionControlHandler {
+ public:
+  CongestionControlHandler(NetworkChangedObserver* observer,
+                           PacedSender* pacer);
+  ~CongestionControlHandler();
+
+  void PostUpdates(NetworkControlUpdate update);
+
+  void OnNetworkAvailability(NetworkAvailability msg);
+  void OnOutstandingData(DataSize in_flight_data);
+  void OnPacerQueueUpdate(TimeDelta expected_queue_time);
+
+  absl::optional<TargetTransferRate> last_transfer_rate();
+
+ private:
+  void SetPacerState(bool paused);
+  void OnNetworkInvalidation();
+  bool IsSendQueueFull() const;
+  bool HasNetworkParametersToReportChanged(int64_t bitrate_bps,
+                                           float loss_rate_ratio,
+                                           TimeDelta rtt);
+
+  bool HasNetworkParametersToReportChanged(int64_t bitrate_bps,
+                                           uint8_t fraction_loss,
+                                           int64_t rtt);
+  NetworkChangedObserver* observer_ = nullptr;
+  PacedSender* const pacer_;
+
+  absl::optional<TargetTransferRate> current_target_rate_msg_;
+  bool network_available_ = true;
+  bool pacer_paused_ = false;
+  int64_t last_reported_target_bitrate_bps_ = 0;
+  uint8_t last_reported_fraction_loss_ = 0;
+  int64_t last_reported_rtt_ms_ = 0;
+  const bool pacer_pushback_experiment_ = false;
+  uint32_t min_pushback_target_bitrate_bps_;
+  int64_t pacer_expected_queue_ms_ = 0;
+  double encoding_rate_ratio_ = 1.0;
+
+  rtc::SequencedTaskChecker sequenced_checker_;
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(CongestionControlHandler);
+};
+}  // namespace webrtc
+#endif  // MODULES_CONGESTION_CONTROLLER_RTP_CONTROL_HANDLER_H_