net: move host_resolver files from net/base to net/dns

net/dns/host_resolver.h

 // 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.
 
-#ifndef NET_BASE_HOST_RESOLVER_H_
-#define NET_BASE_HOST_RESOLVER_H_
+#ifndef NET_DNS_HOST_RESOLVER_H_
+#define NET_DNS_HOST_RESOLVER_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "net/base/address_family.h"
 #include "net/base/completion_callback.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/net_export.h"
 #include "net/base/net_util.h"
 #include "net/base/request_priority.h"
@@ skipping 181 matching lines @@
 
  protected:
   HostResolver();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HostResolver);
 };
 
 }  // namespace net
 
-#endif  // NET_BASE_HOST_RESOLVER_H_
+#endif  // NET_DNS_HOST_RESOLVER_H_