NQE: Record how frequently NetworkID is available

net/nqe/network_quality_estimator.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/nqe/network_quality_estimator.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <utility>
@@ skipping 722 matching lines @@
   RecordMetricsOnConnectionTypeChanged();
 
   // Write the estimates of the previous network to the cache.
   CacheNetworkQualityEstimate();
 
   // Clear the local state.
   last_connection_change_ = tick_clock_->NowTicks();
   peak_network_quality_ = nqe::internal::NetworkQuality();
   downstream_throughput_kbps_observations_.Clear();
   rtt_observations_.Clear();
+
+  // Update the local state for the new connection.

[bengr, 2016/07/08 17:00:07]

I don't understand this comment.

[tbansal1, 2016/07/08 18:39:08]

Reworded.
First, the local state is cleared ("// Clear the local state." comment above).
Then, the local state is updated to reflect the new connection.

   current_network_id_ = GetCurrentNetworkID();
+  RecordNetworkIDAvailability();
 
   // Query the external estimate provider on certain connection types. Once the
   // updated estimates are available, OnUpdatedEstimateAvailable will be called
   // by |external_estimate_provider_| with updated estimates.
   if (external_estimate_provider_ &&
       current_network_id_.type != NetworkChangeNotifier::CONNECTION_NONE &&
       current_network_id_.type != NetworkChangeNotifier::CONNECTION_UNKNOWN &&
       current_network_id_.type != NetworkChangeNotifier::CONNECTION_ETHERNET &&
       current_network_id_.type != NetworkChangeNotifier::CONNECTION_BLUETOOTH) {
     RecordExternalEstimateProviderMetrics(
@@ skipping 74 matching lines @@
                                    base::TimeTicks(), kPercentiles[i]);
 
       transport_rtt_percentile = GetHistogram(
           "TransportRTT.Percentile" + base::IntToString(kPercentiles[i]) + ".",
           current_network_id_.type, 10 * 1000);  // 10 seconds
       transport_rtt_percentile->Add(rtt.InMilliseconds());
     }
   }
 }
 
+void NetworkQualityEstimator::RecordNetworkIDAvailability() const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (current_network_id_.type ==
+          NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI ||
+      NetworkChangeNotifier::IsConnectionCellular(current_network_id_.type)) {
+    UMA_HISTOGRAM_BOOLEAN("NQE.NetworkIdAvailable",
+                          !current_network_id_.id.empty());
+  }
+}
+
 void NetworkQualityEstimator::RecordMetricsOnMainFrameRequest() const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   base::TimeDelta http_rtt;
   if (GetHttpRTTEstimate(&http_rtt)) {
     // Add the 50th percentile value.
     base::HistogramBase* rtt_percentile = GetHistogram(
         "MainFrame.RTT.Percentile50.", current_network_id_.type, 10 * 1000);
     rtt_percentile->Add(http_rtt.InMilliseconds());
   }
@@ skipping 512 matching lines @@
     NotifyObserversOfEffectiveConnectionTypeChanged() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // TODO(tbansal): Add hysteresis in the notification.
   FOR_EACH_OBSERVER(
       EffectiveConnectionTypeObserver, effective_connection_type_observer_list_,
       OnEffectiveConnectionTypeChanged(effective_connection_type_));
 }
 
 }  // namespace net