Expose effective connection type to Cronet

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 c2e9f5d1d42592f23a4e23e322aa2046b02a1560..d38cf0b4f690c7715e97f87253e29231e2423045 100644
--- a/net/nqe/network_quality_estimator.cc
+++ b/net/nqe/network_quality_estimator.cc
@@ -1643,10 +1643,14 @@ void NetworkQualityEstimator::MaybeRecomputeEffectiveConnectionType() {
   // last computed or a connection change event was observed since the last
   // computation. Strict inequalities are used to ensure that effective
   // connection type is recomputed on connection change events even if the clock
-  // has not updated.
+  // has not updated. Recompute the effective connection type if the effective
+  // connection type was previously unavailable. This is because the RTT
+  // observations are voluminous, so it may now be possible to compute the
+  // effective connection type.
   if (now - last_effective_connection_type_computation_ <
           effective_connection_type_recomputation_interval_ &&
-      last_connection_change_ < last_effective_connection_type_computation_) {
+      last_connection_change_ < last_effective_connection_type_computation_ &&
+      effective_connection_type_ != EFFECTIVE_CONNECTION_TYPE_UNKNOWN) {
     return;
   }
 
@@ -1661,6 +1665,7 @@ void NetworkQualityEstimator::MaybeRecomputeEffectiveConnectionType() {
 void NetworkQualityEstimator::
     NotifyObserversOfEffectiveConnectionTypeChanged() {
   DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK_NE(EFFECTIVE_CONNECTION_TYPE_LAST, effective_connection_type_);
 
   // TODO(tbansal): Add hysteresis in the notification.
   FOR_EACH_OBSERVER(