Fixed integer signing bug in cubic bytes/packet implementation

net/quic/core/congestion_control/cubic.h

 // Copyright (c) 2012 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.
 //
 // Cubic algorithm, helper class to TCP cubic.
 // For details see http://netsrv.csc.ncsu.edu/export/cubic_a_new_tcp_2008.pdf.
 
 #ifndef NET_QUIC_CONGESTION_CONTROL_CUBIC_H_
 #define NET_QUIC_CONGESTION_CONTROL_CUBIC_H_
 
@@ skipping 16 matching lines @@
 
   // Call after a timeout to reset the cubic state.
   void Reset();
 
   // Compute a new congestion window to use after a loss event.
   // Returns the new congestion window in packets. The new congestion window is
   // a multiplicative decrease of our current window.
   QuicPacketCount CongestionWindowAfterPacketLoss(QuicPacketCount current);
 
   // Compute a new congestion window to use after a received ACK.
-  // Returns the new congestion window in packets. The new congestion window
-  // follows a cubic function that depends on the time passed since last
-  // packet loss.
+  // Returns the new congestion window in packets. The new congestion
+  // window follows a cubic function that depends on the time passed
+  // since last packet loss.
   QuicPacketCount CongestionWindowAfterAck(QuicPacketCount current,
                                            QuicTime::Delta delay_min);
 
   // Call on ack arrival when sender is unable to use the available congestion
   // window. Resets Cubic state during quiescence.
   void OnApplicationLimited();
 
+  // If true, enable the fix for the convex-mode signing bug.  See
+  // b/32170105 for more information about the bug.

[Zhongyi Shi, 2016/12/01 22:15:23]

nit: you might want to remove this link here.

+  // TODO(jokulik):  Remove once the fix is enabled by default.
+  void SetFixConvexMode(bool fix_convex_mode);
+
  private:
   static const QuicTime::Delta MaxCubicTimeInterval() {
     return QuicTime::Delta::FromMilliseconds(30);
   }
 
   // Compute the TCP Cubic alpha and beta based on the current number of
   // connections.
   float Alpha() const;
   float Beta() const;
 
@@ skipping 33 matching lines @@
 
   // Origin point of cubic function.
   QuicPacketCount origin_point_congestion_window_;
 
   // Time to origin point of cubic function in 2^10 fractions of a second.
   uint32_t time_to_origin_point_;
 
   // Last congestion window in packets computed by cubic function.
   QuicPacketCount last_target_congestion_window_;
 
+  // Fix convex mode for cubic.
+  // TODO(jokulik):  Remove once the cubic convex experiment is done.
+  bool fix_convex_mode_;
+
   DISALLOW_COPY_AND_ASSIGN(Cubic);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CONGESTION_CONTROL_CUBIC_H_