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

net/proxy/proxy_resolver_factory_mojo_unittest.cc

 // Copyright 2015 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 "net/proxy/proxy_resolver_factory_mojo.h"
 
 #include <list>
 #include <map>
 #include <memory>
 #include <queue>
@@ skipping 458 matching lines @@
  public:
   enum Event {
     DNS_REQUEST,
   };
 
   // HostResolver overrides.
   int Resolve(const RequestInfo& info,
               RequestPriority priority,
               AddressList* addresses,
               const CompletionCallback& callback,
-              RequestHandle* request_handle,
+              std::unique_ptr<Request>* request_handle,
               const BoundNetLog& source_net_log) override {
     waiter_.NotifyEvent(DNS_REQUEST);
     return ERR_IO_PENDING;
   }
   int ResolveFromCache(const RequestInfo& info,
                        AddressList* addresses,
                        const BoundNetLog& source_net_log) override {
     return ERR_DNS_CACHE_MISS;
   }
-  void CancelRequest(RequestHandle req) override {}
   HostCache* GetHostCache() override { return nullptr; }
 
   EventWaiter<Event>& waiter() { return waiter_; }
 
  private:
   EventWaiter<Event> waiter_;
 };
 
 void CheckCapturedNetLogEntries(const std::string& expected_string,
                                 const TestNetLogEntry::List& entries) {
@@ skipping 396 matching lines @@
   mock_proxy_resolver_.ClearBlockedClients();
   request->WaitForResult();
 }
 
 TEST_F(ProxyResolverFactoryMojoTest, DeleteResolver) {
   CreateProxyResolver();
   proxy_resolver_mojo_.reset();
   on_delete_callback_.WaitForResult();
 }
 }  // namespace net