net: Fix more clang warnings about missing virtual and OVERRIDE annotations.

net/base/dns_reloader.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/base/dns_reloader.h"
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD) && \
     !defined(OS_ANDROID)
 
 #include <resolv.h>
@@ skipping 66 matching lines @@
       res_nclose(&_res);
     delete reload_state;
   }
 
  private:
   DnsReloader() : resolver_generation_(0) {
     tls_index_.Initialize(SlotReturnFunction);
     net::NetworkChangeNotifier::AddDNSObserver(this);
   }
 
-  ~DnsReloader() {
+  virtual ~DnsReloader() {
     NOTREACHED();  // LeakyLazyInstance is not destructed.
   }
 
   base::Lock lock_;  // Protects resolver_generation_.
   int resolver_generation_;
   friend struct base::DefaultLazyInstanceTraits<DnsReloader>;
 
   // We use thread local storage to identify which ReloadState to interact with.
   static base::ThreadLocalStorage::StaticSlot tls_index_;
 
@@ skipping 18 matching lines @@
 void DnsReloaderMaybeReload() {
   // This routine can be called by any of the DNS worker threads.
   DnsReloader* dns_reloader = g_dns_reloader.Pointer();
   dns_reloader->MaybeReload();
 }
 
 }  // namespace net
 
 #endif  // defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD) &&
         // !defined(OS_ANDROID)