Increase robustness of TestRecordNetworkIDAvailability in NQE

Change-Id: Id6d09819d86e4b9ad258ef7d97fff3c07752c2e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2477657Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817738}

net/nqe/network_quality_estimator_unittest.cc

@@ -2248,9 +2248,13 @@ TEST_F(NetworkQualityEstimatorTest, MAYBE_TestTCPSocketRTT) {
 }
 
 TEST_F(NetworkQualityEstimatorTest, TestRecordNetworkIDAvailability) {
-  base::HistogramTester histogram_tester;
   TestNetworkQualityEstimator estimator;
 
+  // Create the histogram tester after |estimator| is constructed. This ensures
+  // that any network checks done at the time of |estimator| construction do not
+  // affect |histogram_tester|.
+  base::HistogramTester histogram_tester;
+
   // The NetworkID is recorded as available on Wi-Fi connection.
   estimator.SimulateNetworkChange(
       NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI, "test-1");