Update from https://crrev.com/315085

net/http/http_proxy_client_socket_pool.cc

Index: net/http/http_proxy_client_socket_pool.cc
diff --git a/net/http/http_proxy_client_socket_pool.cc b/net/http/http_proxy_client_socket_pool.cc
index 9c8a531778530c6420f9dcd80be1a612baa1ac0f..b97c957cdc8a65a77ab96a9d10f559f09ceb385b 100644
--- a/net/http/http_proxy_client_socket_pool.cc
+++ b/net/http/http_proxy_client_socket_pool.cc
@@ -128,6 +128,10 @@ void HttpProxyConnectJob::GetAdditionalErrorState(ClientSocketHandle * handle) {
 }
 
 void HttpProxyConnectJob::OnIOComplete(int result) {
+  // TODO(pkasting): Remove ScopedTracker below once crbug.com/455884 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455884 HttpProxyConnectJob::OnIOComplete"));
   int rv = DoLoop(result);
   if (rv != ERR_IO_PENDING) {
     NotifyProxyDelegateOfCompletion(rv);