Avoid initial NetworkChangeNotifier OnDNSChanged() signal on Android

net/dns/dns_config_service_unittest.cc

 // Copyright (c) 2012 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/dns/dns_config_service.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/cancelable_callback.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 317 matching lines @@
   last_config_ = bad_config;
   // No change, so no update.
   service_->InvalidateConfig();
   service_->OnConfigRead(config2);
   EXPECT_TRUE(last_config_.Equals(bad_config));
 }
 
 #if (defined(OS_POSIX) && !defined(OS_ANDROID)) || defined(OS_WIN)
 // TODO(szym): This is really an integration test and can time out if HOSTS is
 // huge. http://crbug.com/107810
+// On Android the hosts file is not user modifyable, so it's always tiny,
+// however devices used for testing are likely to have no network connectivity
+// and hence no DNS configuration so this test will just fail to find a valid
+// config.
 TEST_F(DnsConfigServiceTest, DISABLED_GetSystemConfig) {
   service_.reset();
   scoped_ptr<DnsConfigService> service(DnsConfigService::CreateSystemService());
 
   service->ReadConfig(base::Bind(&DnsConfigServiceTest::OnConfigChanged,
                                  base::Unretained(this)));
   base::TimeDelta kTimeout = TestTimeouts::action_max_timeout();
   WaitForConfig(kTimeout);
   ASSERT_TRUE(last_config_.IsValid()) << "Did not receive DnsConfig in " <<
       kTimeout.InSecondsF() << "s";
 }
 #endif  // OS_POSIX || OS_WIN
 
 }  // namespace net