Moved congestion controller to goog_cc folder.

Bug: webrtc:8415
Change-Id: I2070da0cacf1dbfc4b6a89285af3e68fd03497ab
Reviewed-on: https://webrtc-review.googlesource.com/43841
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21928}

modules/congestion_controller/goog_cc/alr_detector.h

@@ -0,0 +1,74 @@
+/*
+ *  Copyright (c) 2016 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_GOOG_CC_ALR_DETECTOR_H_
+#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_ALR_DETECTOR_H_
+
+#include "api/optional.h"
+#include "common_types.h"  // NOLINT(build/include)
+#include "modules/pacing/interval_budget.h"
+#include "modules/pacing/paced_sender.h"
+#include "rtc_base/rate_statistics.h"
+#include "typedefs.h"  // NOLINT(build/include)
+
+namespace webrtc {
+
+class RtcEventLog;
+
+// Application limited region detector is a class that utilizes signals of
+// elapsed time and bytes sent to estimate whether network traffic is
+// currently limited by the application's ability to generate traffic.
+//
+// AlrDetector provides a signal that can be utilized to adjust
+// estimate bandwidth.
+// Note: This class is not thread-safe.
+class AlrDetector {
+ public:
+  AlrDetector();
+  explicit AlrDetector(RtcEventLog* event_log);
+  ~AlrDetector();
+
+  void OnBytesSent(size_t bytes_sent, int64_t send_time_ms);
+
+  // Set current estimated bandwidth.
+  void SetEstimatedBitrate(int bitrate_bps);
+
+  // Returns time in milliseconds when the current application-limited region
+  // started or empty result if the sender is currently not application-limited.
+  rtc::Optional<int64_t> GetApplicationLimitedRegionStartTime() const;
+
+  // Sent traffic percentage as a function of network capacity used to determine
+  // application-limited region. ALR region start when bandwidth usage drops
+  // below kAlrStartUsagePercent and ends when it raises above
+  // kAlrEndUsagePercent. NOTE: This is intentionally conservative at the moment
+  // until BW adjustments of application limited region is fine tuned.
+  static constexpr int kDefaultAlrBandwidthUsagePercent = 65;
+  static constexpr int kDefaultAlrStartBudgetLevelPercent = 80;
+  static constexpr int kDefaultAlrStopBudgetLevelPercent = 50;
+
+  void UpdateBudgetWithElapsedTime(int64_t delta_time_ms);
+  void UpdateBudgetWithBytesSent(size_t bytes_sent);
+
+ private:
+  int bandwidth_usage_percent_;
+  int alr_start_budget_level_percent_;
+  int alr_stop_budget_level_percent_;
+
+  rtc::Optional<int64_t> last_send_time_ms_;
+
+  IntervalBudget alr_budget_;
+  rtc::Optional<int64_t> alr_started_time_ms_;
+
+  RtcEventLog* event_log_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_CONGESTION_CONTROLLER_GOOG_CC_ALR_DETECTOR_H_