=============
ERROR at //net/proxy/proxy_config_service_linux.cc:44:11: Include not allowed.
#include "library_loaders/libgio.h"
          ^-----------------------
It is not in any dependency of
  //net:net

===========
#if defined(USE_GIO)
#include "library_loaders/libgio.h"
#endif  // defined(USE_GIO)

===========

so, USE_GIO is true. 

which is expected, since 

use_gio = is_linux && !is_chromeos && !is_chromecast && !is_headless

Any idea why this wouldn't have been caught on the trybot?  Maybe our trybot is still building for chromeos?

Looks like this failed in build 290, succeeded for three builds, then failed again in 294. Running the same command-line locally works fine for me; re-testing w/ my checko-out updated to ToT.

if it was building for ChromeOS, then use_gio was false and thus no error.

But, local build has use_gio be true and no build error. 

Re #4: It's not the actual build that's failing, but gn gen --check; are you running that with the parameters from the builder log?

I'm able to repro the gn gen --check failure locally, FWIW.

Seems quick enough to bisect; will update bug when I find what broke it. There were some gncheck related CLs touching net in there, I notice, but I didn't see any reason why they'd break things at a glance.

Confirmed that the culprit was https://codereview.chromium.org/1812243002, but all that did was fix some things and then remove the gncheck suppression from net/.

It appears to be the use_ozone=true that triggers the failure, which should give us a hint as to where to find that dependency.

Looking at net/proxy/proxy_config_service_linux.cc and net/BUILD.gn, the include is guarded by USE_GIO while the GN dependencies are guarded by use_glib and use_gconf && !is_chromeos, or is_desktop_linux in the other case; if we can confirm that use_gio is set correctly based on the other flags then I'd suggest we just use that in the BUILD.gn.

Haibin, can you take a look?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a872526808bc606a6e0df788131de626eaaeea82

commit a872526808bc606a6e0df788131de626eaaeea82
Author: haibinlu <haibinlu@chromium.org>
Date: Tue Mar 22 22:58:33 2016

Supress gn check error in proxy_config_service_linux.cc

Background on nogncheck

https://groups.google.com/a/chromium.org/forum/#!msg/chromium-dev/ctwaYl__aaQ/u12ZIlv21gIJ

BUG= 596706 

Review URL: https://codereview.chromium.org/1827623002

Cr-Commit-Position: refs/heads/master@{#382719}

[modify] https://crrev.com/a872526808bc606a6e0df788131de626eaaeea82/net/proxy/proxy_config_service_linux.cc