Expire but don't clear HostCache on DNS config change

components/cronet/stale_host_resolver_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 "components/cronet/stale_host_resolver.h"
 
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
@@ skipping 144 matching lines @@
 
     base::TimeDelta ttl(base::TimeDelta::FromSeconds(kCacheEntryTTLSec));
     net::HostCache::Key key(kHostname, net::ADDRESS_FAMILY_IPV4, 0);
     net::HostCache::Entry entry(net::OK, MakeAddressList(kCacheAddress), ttl);
     base::TimeDelta age = base::TimeDelta::FromSeconds(age_sec);
     base::TimeTicks then = base::TimeTicks::Now() - age;
     resolver_->GetHostCache()->Set(key, entry, then, ttl);
   }
 
   void OnNetworkChange() {
+    // Real network changes on Android will send both notifications.
     net::NetworkChangeNotifier::NotifyObserversOfIPAddressChangeForTests();
+    net::NetworkChangeNotifier::NotifyObserversOfDNSChangeForTests();
     base::RunLoop().RunUntilIdle();  // Wait for notification.
   }
 
   void LookupStale() {
     DCHECK(resolver_);
     DCHECK(resolver_->GetHostCache());
 
     net::HostCache::Key key(kHostname, net::ADDRESS_FAMILY_IPV4, 0);
     base::TimeTicks now = base::TimeTicks::Now();
     const net::HostCache::Entry* entry;
@@ skipping 327 matching lines @@
 
   EXPECT_TRUE(resolve_complete());
   EXPECT_EQ(net::OK, resolve_error());
   EXPECT_EQ(1u, resolve_addresses().size());
   EXPECT_EQ(kCacheAddress, resolve_addresses()[0].ToStringWithoutPort());
 }
 
 }  // namespace
 
 }  // namespace cronet