make ProxyService::CreateSystemProxyConfigService return scoped_ptrs

ios/crnet/crnet_environment.mm

Index: ios/crnet/crnet_environment.mm
diff --git a/ios/crnet/crnet_environment.mm b/ios/crnet/crnet_environment.mm
index c8650cb0483aefc12390c79bc7e11c6ccc3d2d3f..9551102bb7b0a8c6ec9dbc5df1455efb799f9b63 100644
--- a/ios/crnet/crnet_environment.mm
+++ b/ios/crnet/crnet_environment.mm
@@ -282,8 +282,8 @@ void CrNetEnvironment::Install() {
   // The network change notifier must be initialized so that registered
   // delegates will receive callbacks.
   network_change_notifier_.reset(net::NetworkChangeNotifier::Create());
-  proxy_config_service_.reset(net::ProxyService::CreateSystemProxyConfigService(
-      network_io_thread_->task_runner(), nullptr));
+  proxy_config_service_ = net::ProxyService::CreateSystemProxyConfigService(
+      network_io_thread_->task_runner(), nullptr);
 
   PostToNetworkThread(FROM_HERE,
       base::Bind(&CrNetEnvironment::InitializeOnNetworkThread,
@@ -408,7 +408,7 @@ void CrNetEnvironment::InitializeOnNetworkThread() {
           .release());
   main_context_->set_proxy_service(
       net::ProxyService::CreateUsingSystemProxyResolver(
-          proxy_config_service_.get(), 0, nullptr)
+          proxy_config_service_.Pass(), 0, nullptr)

[Randy Smith (Not in Mondays), 2015/09/18 20:14:55]

This is a semantic change; did you trace code to make sure it's safe?  (i.e. no
one else touching proxy_config_service_ again, it never being deleted)

[mmenke, 2015/09/18 20:31:10]

This change actually fixes a double delete, I believe.

[Randy Smith (Not in Mondays), 2015/09/18 20:35:03]

Best kind of semantic change :-}.

[Charlie Harrison, 2015/09/21 16:47:04]

Yeah I believe this is the only time proxy_config_service_ is needed by the
class. There's only that brief window of ownership.

           .release());
 
   // Cache