Notify NQE of TCP RTT values

net/base/socket_performance_watcher.cc

 // 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.
 
 #include "net/base/socket_performance_watcher.h"
 
 #include "base/logging.h"
 
 namespace net {
 
 SocketPerformanceWatcher::SocketPerformanceWatcher(
-    const SocketPerformanceWatcherFactory::Protocol protocol,
+    SocketPerformanceWatcherFactory::Protocol protocol,
     SocketPerformanceWatcherFactory* socket_performance_watcher_factory)
     : protocol_(protocol),
+      rtt_notification_received_count_(0),
       socket_performance_watcher_factory_(socket_performance_watcher_factory) {
   DCHECK(socket_performance_watcher_factory_);
 
   switch (protocol) {
     case SocketPerformanceWatcherFactory::PROTOCOL_TCP:
     case SocketPerformanceWatcherFactory::PROTOCOL_QUIC:
       return;
     default:
       NOTREACHED();
   }
 }
 
 SocketPerformanceWatcher::~SocketPerformanceWatcher() {}
 
 void SocketPerformanceWatcher::OnUpdatedRTTAvailable(
-    const base::TimeDelta& rtt) const {
+    const base::TimeDelta& rtt) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  rtt_notification_received_count_++;
   socket_performance_watcher_factory_->OnUpdatedRTTAvailable(protocol_, rtt);
 }
 
+bool SocketPerformanceWatcher::ShouldNotifyUpdatedRTT() const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // Currently using a small value until crbug.com/590300 is fixed. TCP/QUIC
+  // start with a hard-coded RTT estimate, and converge to a more accurate value
+  // as more packets are received. This means that SPW should receive frequent
+  // RTT notifications when the TCP/QUIC connection has just started, and less
+  // frequent notification afterwards.
+  return rtt_notification_received_count_ < 1;
+}
+
+void SocketPerformanceWatcher::Reset() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  rtt_notification_received_count_ = 0;
+  socket_performance_watcher_factory_->OnWatcherReset();
+}
+
 }  // namespace net