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

net/dns/dns_config_service_posix.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_posix.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
@@ skipping 53 matching lines @@
 }
 
 // A SerialWorker that uses libresolv to initialize res_state and converts
 // it to DnsConfig.
 class ConfigReader : public SerialWorker {
  public:
   typedef base::Callback<void(const DnsConfig& config)> CallbackType;
   explicit ConfigReader(const CallbackType& callback)
       : callback_(callback), success_(false) {}
 
-  void DoWork() OVERRIDE {
+  virtual void DoWork() OVERRIDE {
     base::TimeTicks start_time = base::TimeTicks::Now();
     ConfigParsePosixResult result = ReadDnsConfig(&dns_config_);
     success_ = (result == CONFIG_PARSE_POSIX_OK);
     UMA_HISTOGRAM_ENUMERATION("AsyncDNS.ConfigParsePosix",
                               result, CONFIG_PARSE_POSIX_MAX);
     UMA_HISTOGRAM_BOOLEAN("AsyncDNS.ConfigParseResult", success_);
     UMA_HISTOGRAM_TIMES("AsyncDNS.ConfigParseDuration",
                         base::TimeTicks::Now() - start_time);
   }
 
-  void OnWorkFinished() OVERRIDE {
+  virtual void OnWorkFinished() OVERRIDE {
     DCHECK(!IsCancelled());
     if (success_) {
       callback_.Run(dns_config_);
     } else {
       LOG(WARNING) << "Failed to read DnsConfig.";
     }
   }
 
  private:
   virtual ~ConfigReader() {}
@@ skipping 189 matching lines @@
   virtual ~StubDnsConfigService() {}
   virtual void OnDNSChanged(unsigned detail) OVERRIDE {}
 };
 // static
 scoped_ptr<DnsConfigService> DnsConfigService::CreateSystemService() {
   return scoped_ptr<DnsConfigService>(new StubDnsConfigService());
 }
 #endif
 
 }  // namespace net