First step to remove SingleRequestHostResolver.

content/browser/renderer_host/pepper/pepper_lookup_request.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 CONTENT_BROWSER_RENDERER_HOST_PEPPER_PEPPER_LOOKUP_REQUEST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_PEPPER_PEPPER_LOOKUP_REQUEST_H_
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "net/base/address_list.h"
 #include "net/base/net_errors.h"
 #include "net/dns/host_resolver.h"
-#include "net/dns/single_request_host_resolver.h"
 
 namespace content {
 
 template <class T>
 class PepperLookupRequest {
  public:
   typedef base::Callback<void(int, const net::AddressList&, const T&)>
       LookupRequestCallback;
 
   // Takes ownership over |bound_info|. |bound_info| will be passed to
   // callback, when lookup will finish.
   PepperLookupRequest(net::HostResolver* resolver,
                       const net::HostResolver::RequestInfo& request_info,
                       net::RequestPriority priority,
                       T* bound_info,
                       const LookupRequestCallback& callback)
       : resolver_(resolver),
         request_info_(request_info),
         priority_(priority),
         bound_info_(bound_info),
         callback_(callback) {}
 
   void Start() {
     int result =
-        resolver_.Resolve(request_info_,
-                          priority_,
-                          &addresses_,
-                          base::Bind(&PepperLookupRequest<T>::OnLookupFinished,
-                                     base::Unretained(this)),
-                          net::BoundNetLog());
+        resolver_->Resolve(request_info_, priority_, &addresses_,
+                           base::Bind(&PepperLookupRequest<T>::OnLookupFinished,
+                                      base::Unretained(this)),
+                           &request_, net::BoundNetLog());
     if (result != net::ERR_IO_PENDING)
       OnLookupFinished(result);
   }
 
  private:
   void OnLookupFinished(int result) {
     callback_.Run(result, addresses_, *bound_info_);
     delete this;
   }
 
-  net::SingleRequestHostResolver resolver_;
+  net::HostResolver* resolver_;
+  std::unique_ptr<net::HostResolver::Request> request_;
   net::HostResolver::RequestInfo request_info_;
   net::RequestPriority priority_;
   std::unique_ptr<T> bound_info_;
   LookupRequestCallback callback_;
 
   net::AddressList addresses_;
 
   DISALLOW_COPY_AND_ASSIGN(PepperLookupRequest);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_PEPPER_PEPPER_LOOKUP_REQUEST_H_