Reference count ProxyService....

net/proxy/proxy_service.cc

 // Copyright (c) 2006-2008 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_service.h"
 
 #include <algorithm>
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
@@ skipping 168 matching lines @@
     // Remove this completed PacRequest from the service's pending list.
     /// (which will probably cause deletion of |this|).
     CompletionCallback* callback = user_callback_;
     service_->RemovePendingRequest(this);
 
     callback->Run(result_code);
   }
 
   ProxyResolver* resolver() const { return service_->resolver_.get(); }
 
+  // Note that we don't hold a reference to the ProxyService. Outstanding
+  // requests are cancelled during ~ProxyService, so this is guaranteed
+  // to be valid throughout our lifetime.
   ProxyService* service_;
   CompletionCallback* user_callback_;
   CompletionCallbackImpl<PacRequest> io_callback_;
   ProxyInfo* results_;
   GURL url_;
   ProxyResolver::RequestHandle resolve_job_;
   ProxyConfig::ID config_id_;  // The config id when the resolve was started.
   scoped_refptr<LoadLog> load_log_;
 };
 
@@ skipping 587 matching lines @@
     OnCompletion(result_);
   }
 }
 
 void SyncProxyServiceHelper::OnCompletion(int rv) {
   result_ = rv;
   event_.Signal();
 }
 
 }  // namespace net