Certificate Transparency: Ensure no observers in STHDistributor d'tor.

net/cert/sth_distributor_unittest.cc

 // Copyright 2016 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/cert/sth_distributor.h"
 
 #include <map>
 #include <string>
 
 #include "base/test/histogram_tester.h"
@@ skipping 48 matching lines @@
   distributor_.NewSTHObserved(sample_sth_);
   distributor_.NewSTHObserved(second_sth);
 
   StoringSTHObserver observer;
   distributor_.RegisterObserver(&observer);
 
   // Check that two STHs from different logs received prior to observer
   // registration were reported to the observer once registered.
   EXPECT_EQ(2u, observer.sths.size());
   EXPECT_EQ(1u, observer.sths.count(other_log));
+  distributor_.UnregisterObserver(&observer);
 }
 
 // Test that histograms are properly recorded for the STH age when an STH
 // from Google's Pilot log is observed.
 TEST_F(STHDistributorTest, LogsUMAForPilotSTH) {
   const char kPilotSTHAgeHistogram[] =
       "Net.CertificateTransparency.PilotSTHAge";
   base::HistogramTester histograms;
   histograms.ExpectTotalCount(kPilotSTHAgeHistogram, 0);
 
@@ skipping 38 matching lines @@
   EXPECT_NE(sample_sth_, observer.sths[GetTestPublicKeyId()]);
   EXPECT_EQ(new_sth, observer.sths[GetTestPublicKeyId()]);
 
   // Registering a new observer should only receive the most recently observed
   // STH.
   StoringSTHObserver new_observer;
   distributor_.RegisterObserver(&new_observer);
   EXPECT_EQ(1u, new_observer.sths.size());
   EXPECT_NE(sample_sth_, new_observer.sths[GetTestPublicKeyId()]);
   EXPECT_EQ(new_sth, new_observer.sths[GetTestPublicKeyId()]);
+
+  distributor_.UnregisterObserver(&new_observer);
+  distributor_.UnregisterObserver(&observer);
 }
 
 }  // namespace
 
 }  // namespace ct
 
 }  // namespace net