Expose packet loss counts from QUIC to NetworkQualityEstimator

net/base/socket_performance_watcher.h

 // Copyright 2015 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.
 
 #ifndef NET_BASE_SOCKET_PERFORMANCE_WATCHER_H_
 #define NET_BASE_SOCKET_PERFORMANCE_WATCHER_H_
 
+#include <stddef.h>
+
 #include "base/macros.h"
 #include "net/base/net_export.h"
 #include "net/base/socket_performance_watcher_factory.h"
 
 namespace base {
 class TimeDelta;
 }  // namespace base
 
 namespace net {
 
 // SocketPerformanceWatcher is the base class for recording and aggregating
 // socket statistics.
 class NET_EXPORT_PRIVATE SocketPerformanceWatcher {
  public:
   // |socket_performance_watcher_factory| is the factory that constructed
   // |this| watcher.
   SocketPerformanceWatcher(
       const SocketPerformanceWatcherFactory::Protocol protocol,
       SocketPerformanceWatcherFactory* socket_performance_watcher_factory);
 
   virtual ~SocketPerformanceWatcher();
 
   // Called when updated transport layer RTT information is available. This
   // must be the transport layer RTT from this device to the remote transport
   // layer endpoint. This method is called immediately after the observation is
   // made, hence no timestamp.
   void OnUpdatedRTTAvailable(const base::TimeDelta& rtt) const;
 
+  // Called when the incremental packet counts at the transport layer are
+  // available. All the counts are since the last call to the
+  // OnIncrementalPacketCountAvailable. This method is called immediately after
+  // the observation is made, hence no timestamp.
+
+  // An example:
+  // Last observation after packet #1. Packets #5 and #6 are received:
+  //   missing = 3, in_order = 2, out_of_order = 0.
+
+  // Last observation after packet #6. Packet #3 received:
+  //   missing = 0, in_order = 0, out_of_order = 1.
+  void OnIncrementalPacketCountAvailable(
+      size_t packets_missing,
+      size_t packets_received_in_order,
+      size_t packets_received_out_of_order) const;
+
  private:
   // Transport layer protocol used by the socket that |this| is watching.
   const SocketPerformanceWatcherFactory::Protocol protocol_;
 
   // |socket_performance_watcher_factory_| is the factory that created
   // |this| watcher.
   SocketPerformanceWatcherFactory* socket_performance_watcher_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SocketPerformanceWatcher);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_SOCKET_PERFORMANCE_WATCHER_H_