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diff --git a/chromium/net/quic/congestion_control/channel_estimator.h b/chromium/net/quic/congestion_control/channel_estimator.h
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+++ b/chromium/net/quic/congestion_control/channel_estimator.h
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+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Based on the inter arrival time of the received packets relative to the time
+// those packets where sent we can estimate the max capacity of the channel.
+// We can only use packet pair that are sent out faster than the acctual
+// channel capacity.
+#ifndef NET_QUIC_CONGESTION_CONTROL_CHANNEL_ESTIMATOR_H_
+#define NET_QUIC_CONGESTION_CONTROL_CHANNEL_ESTIMATOR_H_
+
+#include <list>
+#include <map>
+
+#include "base/basictypes.h"
+#include "net/base/net_export.h"
+#include "net/quic/congestion_control/quic_max_sized_map.h"
+#include "net/quic/quic_bandwidth.h"
+#include "net/quic/quic_protocol.h"
+#include "net/quic/quic_time.h"
+
+namespace net {
+
+enum ChannelEstimateState {
+  kChannelEstimateUnknown = 0,
+  kChannelEstimateUncertain = 1,
+  kChannelEstimateGood = 2
+};
+
+class NET_EXPORT_PRIVATE ChannelEstimator {
+ public:
+  ChannelEstimator();
+  ~ChannelEstimator();
+
+  // This method should be called each time we acquire a receive time for a
+  // packet we previously sent.  It calculates deltas between consecutive
+  // receive times, and may use that to update the channel bandwidth estimate.
+  void OnAcknowledgedPacket(QuicPacketSequenceNumber sequence_number,
+                            QuicByteCount packet_size,
+                            QuicTime send_time,
+                            QuicTime receive_time);
+
+  // Get the current estimated state and channel capacity.
+  // Note: estimate will not be valid when kChannelEstimateUnknown is returned.
+  ChannelEstimateState GetChannelEstimate(QuicBandwidth* estimate) const;
+
+ private:
+  void UpdateFilter(QuicTime::Delta received_delta, QuicByteCount size_delta,
+                    QuicPacketSequenceNumber sequence_number);
+
+  QuicPacketSequenceNumber last_sequence_number_;
+  QuicTime last_send_time_;
+  QuicTime last_receive_time_;
+  QuicMaxSizedMap<QuicBandwidth, QuicPacketSequenceNumber>
+      sorted_bitrate_estimates_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChannelEstimator);
+};
+
+}  // namespace net
+#endif  // NET_QUIC_CONGESTION_CONTROL_CHANNEL_ESTIMATOR_H_