Linux: Monitor resolv.conf for changes and use that to reload resolver.

net/base/host_resolver_impl.h

 // Copyright (c) 2011 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.
 
 #ifndef NET_BASE_HOST_RESOLVER_IMPL_H_
 #define NET_BASE_HOST_RESOLVER_IMPL_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 44 matching lines @@
 //
 // Whenever we try to resolve the host, we post a delayed task to check if host
 // resolution (OnLookupComplete) is completed or not. If the original attempt
 // hasn't completed, then we start another attempt for host resolution. We take
 // the results from the first attempt that finishes and ignore the results from
 // all other attempts.
 
 class NET_EXPORT HostResolverImpl
     : public HostResolver,
       NON_EXPORTED_BASE(public base::NonThreadSafe),
-      public NetworkChangeNotifier::IPAddressObserver {
+      public NetworkChangeNotifier::IPAddressObserver,
+      public NetworkChangeNotifier::DNSObserver {
  public:
   // The index into |job_pools_| for the various job pools. Pools with a higher
   // index have lower priority.
   //
   // Note: This is currently unused, since there is a single pool
   //       for all requests.
   enum JobPoolIndex {
     POOL_NORMAL = 0,
     POOL_COUNT,
   };
@@ skipping 221 matching lines @@
   }
 
   // Helper methods to get and set retry_factor_.
   uint32 retry_factor() const {
     return retry_factor_;
   }
   void set_retry_factor(const uint32 retry_factor) {
     retry_factor_ = retry_factor;
   }
 
+  // NetworkChangeNotifier::OnDNSChanged methods:
+  virtual void OnDNSChanged();
+
   // Cache of host resolution results.
   scoped_ptr<HostCache> cache_;
 
   // Map from hostname to outstanding job.
   JobMap jobs_;
 
   // Maximum number of concurrent jobs allowed, across all pools. Each job may
   // create multiple concurrent resolve attempts for the hostname.
   size_t max_jobs_;
 
@@ skipping 47 matching lines @@
   HostResolverFlags additional_resolver_flags_;
 
   NetLog* net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(HostResolverImpl);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_HOST_RESOLVER_IMPL_H_