Eric:  Are you planning on working on this, or not?  (Not trying to imply you should be working on this or anything, just get the impression that you may be planning to)

I am touching the code as part of  issue 680837 , and in the short term was just going to link to this bug number in a TODO.

I can do an intermediary extraction of code to a helper if that comes up in our review. Otherwise it is probably simpler to defer to after the GCM code is removed.

I don't mind taking this, but will leave it open to reflect I am not working on it yet.

Hmm, I should probably just take this :)

Thanks, Eric. I filed  bug 817094  to eliminate the copy in gcm. I plan to start working on it soon.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6f8003358567c900f05a277707d3fb3783a4c722

commit 6f8003358567c900f05a277707d3fb3783a4c722
Author: Eric Roman <eroman@chromium.org>
Date: Thu Mar 01 22:49:14 2018

Refactor duplicated implementations of ReconsiderProxyAfterError.

This extracts the logic for categorizing network errors as retry-able proxy errors to proxy_fallback.cc.

It is a bit awkward to have a single function in this file, however it serves as a good place to document general proxy fallback behaviors, and the more logic from proxy fallback could be moved here in the future.

Bug:  817052 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: Ic6356c4de3012c41a4bc91feb1e71b5586330fa0
Reviewed-on: https://chromium-review.googlesource.com/940626
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Helen Li <xunjieli@chromium.org>
Commit-Queue: Eric Roman <eroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540324}
[modify] https://crrev.com/6f8003358567c900f05a277707d3fb3783a4c722/google_apis/gcm/engine/connection_factory_impl.cc
[modify] https://crrev.com/6f8003358567c900f05a277707d3fb3783a4c722/net/BUILD.gn
[modify] https://crrev.com/6f8003358567c900f05a277707d3fb3783a4c722/net/http/http_stream_factory_impl_job.cc
[add] https://crrev.com/6f8003358567c900f05a277707d3fb3783a4c722/net/http/proxy_fallback.cc
[add] https://crrev.com/6f8003358567c900f05a277707d3fb3783a4c722/net/http/proxy_fallback.h
[modify] https://crrev.com/6f8003358567c900f05a277707d3fb3783a4c722/services/network/proxy_resolving_client_socket.cc
[modify] https://crrev.com/6f8003358567c900f05a277707d3fb3783a4c722/services/network/proxy_resolving_client_socket_unittest.cc