NQE: Record the main frame metrics at transaction start

net/nqe/network_quality_estimator.cc

Index: net/nqe/network_quality_estimator.cc
diff --git a/net/nqe/network_quality_estimator.cc b/net/nqe/network_quality_estimator.cc
index daa50cd7f4f09663b57660e92f621dc1980382c9..c92ed5286653fac450eb106402b4b326c424c4a5 100644
--- a/net/nqe/network_quality_estimator.cc
+++ b/net/nqe/network_quality_estimator.cc
@@ -402,25 +402,11 @@ void NetworkQualityEstimator::NotifyStartTransaction(
   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();
@@ -444,6 +430,25 @@ void NetworkQualityEstimator::NotifyHeadersReceived(const URLRequest& request) {
           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);
@@ -468,9 +473,9 @@ void NetworkQualityEstimator::NotifyHeadersReceived(const URLRequest& request) {
         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);
 }