NQE: Record the main frame metrics at transaction start

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 384 matching lines @@
   return accuracy_recording_intervals_;
 }
 
 void NetworkQualityEstimator::NotifyStartTransaction(
     const URLRequest& request) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (!RequestSchemeIsHTTPOrHTTPS(request))
     return;
 
-  throughput_analyzer_->NotifyStartTransaction(request);
-}
-
-void NetworkQualityEstimator::NotifyHeadersReceived(const URLRequest& request) {
-  TRACE_EVENT0(kNetTracingCategory,
-               "NetworkQualityEstimator::NotifyHeadersReceived");
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  if (!RequestSchemeIsHTTPOrHTTPS(request) ||
-      !RequestProvidesRTTObservation(request)) {
-    return;
-  }
-
-  const base::TimeTicks now = tick_clock_->NowTicks();
-
   // Update |estimated_quality_at_last_main_frame_| if this is a main frame
   // request.
   // TODO(tbansal): Refactor this to a separate method.
   if (request.load_flags() & LOAD_MAIN_FRAME_DEPRECATED) {
+    base::TimeTicks now = tick_clock_->NowTicks();
     last_main_frame_request_ = now;
 
     ComputeEffectiveConnectionType();
     effective_connection_type_at_last_main_frame_ = effective_connection_type_;
     estimated_quality_at_last_main_frame_ = network_quality_;
 
     RecordMetricsOnMainFrameRequest();
     MaybeQueryExternalEstimateProvider();
 
     // Post the tasks which will run in the future and record the estimation
     // accuracy based on the observations received between now and the time of
     // task execution. Posting the task at different intervals makes it
     // possible to measure the accuracy by comparing the estimate with the
     // observations received over intervals of varying durations.
     for (const base::TimeDelta& measuring_delay :
          GetAccuracyRecordingIntervals()) {
       base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
           FROM_HERE,
           base::Bind(&NetworkQualityEstimator::RecordAccuracyAfterMainFrame,
                      weak_ptr_factory_.GetWeakPtr(), measuring_delay),
           measuring_delay);
     }
   }
+  throughput_analyzer_->NotifyStartTransaction(request);
+}
+
+void NetworkQualityEstimator::NotifyHeadersReceived(const URLRequest& request) {
+  TRACE_EVENT0(kNetTracingCategory,
+               "NetworkQualityEstimator::NotifyHeadersReceived");
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (!RequestSchemeIsHTTPOrHTTPS(request) ||
+      !RequestProvidesRTTObservation(request)) {
+    return;
+  }
+
+  // Update |estimated_quality_at_last_main_frame_| if this is a main frame
+  // request.
+  // TODO(tbansal): Refactor this to a separate method.
+  if (request.load_flags() & LOAD_MAIN_FRAME_DEPRECATED) {
+    ComputeEffectiveConnectionType();
+  }
 
   LoadTimingInfo load_timing_info;
   request.GetLoadTimingInfo(&load_timing_info);
 
   // If the load timing info is unavailable, it probably means that the request
   // did not go over the network.
   if (load_timing_info.send_start.is_null() ||
       load_timing_info.receive_headers_end.is_null()) {
     return;
   }
   DCHECK(!request.response_info().was_cached);
 
   // Duration between when the resource was requested and when the response
   // headers were received.
   base::TimeDelta observed_http_rtt =
       load_timing_info.receive_headers_end - load_timing_info.send_start;
   DCHECK_GE(observed_http_rtt, base::TimeDelta());
   if (observed_http_rtt < peak_network_quality_.http_rtt() ||
       peak_network_quality_.http_rtt() == nqe::internal::InvalidRTT()) {
     peak_network_quality_ = nqe::internal::NetworkQuality(
         observed_http_rtt, peak_network_quality_.transport_rtt(),
         peak_network_quality_.downstream_throughput_kbps());
   }
 
-  RttObservation http_rtt_observation(observed_http_rtt, now,
-                                      signal_strength_dbm_,
-                                      NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP);
+  RttObservation http_rtt_observation(
+      observed_http_rtt, tick_clock_->NowTicks(), signal_strength_dbm_,
+      NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP);
   rtt_observations_.AddObservation(http_rtt_observation);
   NotifyObserversOfRTT(http_rtt_observation);
 }
 
 void NetworkQualityEstimator::RecordAccuracyAfterMainFrame(
     base::TimeDelta measuring_duration) const {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK_EQ(0, measuring_duration.InMilliseconds() % 1000);
   DCHECK(ContainsValue(GetAccuracyRecordingIntervals(), measuring_duration));
 
@@ skipping 1263 matching lines @@
         NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_CACHED_ESTIMATE);
     downstream_throughput_kbps_observations_.AddObservation(
         throughput_observation);
     NotifyObserversOfThroughput(throughput_observation);
   }
 
   ComputeEffectiveConnectionType();
 }
 
 }  // namespace net