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

extensions/browser/api/sockets_tcp/sockets_tcp_api.cc

 // Copyright 2014 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 "extensions/browser/api/sockets_tcp/sockets_tcp_api.h"
 
 #include "base/memory/ptr_util.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/storage_partition.h"
 #include "content/public/common/socket_permission_request.h"
@@ skipping 271 matching lines @@
 
   StartDnsLookup(net::HostPortPair(params_->peer_address, params_->peer_port));
 }
 
 void SocketsTcpConnectFunction::AfterDnsLookup(int lookup_result) {
   if (lookup_result == net::OK) {
     StartConnect();
   } else {
     OnCompleted(lookup_result);
   }
+
+  // TODO(maksims): investigate why std::unique_ptr<HostResolver::Request>'s
+  // destructor is not called automatically.
+  request_handle_.reset();
 }
 
 void SocketsTcpConnectFunction::StartConnect() {
   ResumableTCPSocket* socket = GetTcpSocket(params_->socket_id);
   if (!socket) {
     error_ = kSocketNotFoundError;
     AsyncWorkCompleted();
     return;
   }
 
@@ skipping 236 matching lines @@
     RemoveSocket(params_->socket_id);
     error_ = net::ErrorToString(result);
   }
 
   results_ = api::sockets_tcp::Secure::Results::Create(result);
   AsyncWorkCompleted();
 }
 
 }  // namespace api
 }  // namespace extensions