Change HostResolver::Resolve() to take an std::unique_ptr<Request>* rather than a RequestHandle*

net/dns/single_request_host_resolver.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_DNS_SINGLE_REQUEST_HOST_RESOLVER_H_
 #define NET_DNS_SINGLE_REQUEST_HOST_RESOLVER_H_
 
 #include "base/macros.h"
 #include "net/base/completion_callback.h"
 #include "net/base/net_export.h"
@@ skipping 32 matching lines @@
 
  private:
   // Callback for when the request to |resolver_| completes, so we dispatch
   // to the user's callback.
   void OnResolveCompletion(int result);
 
   // The actual host resolver that will handle the request.
   HostResolver* const resolver_;
 
   // The current request (if any).
-  HostResolver::RequestHandle cur_request_;
+  std::unique_ptr<HostResolver::Request> cur_request_;
   CompletionCallback cur_request_callback_;
 
   // Completion callback for when request to |resolver_| completes.
   CompletionCallback callback_;
 
   DISALLOW_COPY_AND_ASSIGN(SingleRequestHostResolver);
 };
 
 }  // namespace net
 
 #endif  // NET_DNS_SINGLE_REQUEST_HOST_RESOLVER_H_