The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0066f73c3e3cba1cd9d57337465d900d34eedb3f

commit 0066f73c3e3cba1cd9d57337465d900d34eedb3f
Author: stkhapugin@chromium.org <stkhapugin@chromium.org>
Date: Thu Dec 28 10:44:32 2017

Add a presubmit check for ARC compile guards in new .mm files for iOS.

Implements a new presubmit check that verifies that newly created .mm
files have a proper compile guard.

For example:

$ touch ios/asdf.mm
$ git commit -am "asdf" && git cl upload

Running presubmit upload checks ...

** Presubmit ERRORS **
Found new Objective-C implementation file without compile guard. Please use the following compile guard:
#if !defined(__has_feature) || !__has_feature(objc_arc)
#error "This file requires ARC support."
#endif

ios/asdf.mm


Bug:  762461 
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ice720c8ddf5db2f11b12e56c0877619d612fa9ef
Reviewed-on: https://chromium-review.googlesource.com/844696
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526292}
[modify] https://crrev.com/0066f73c3e3cba1cd9d57337465d900d34eedb3f/ios/PRESUBMIT.py
[modify] https://crrev.com/0066f73c3e3cba1cd9d57337465d900d34eedb3f/ios/PRESUBMIT_test.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d7eac5cca81d054abf2ebd76919a4d3fb43e3d94

commit d7eac5cca81d054abf2ebd76919a4d3fb43e3d94
Author: stkhapugin@chromium.org <stkhapugin@chromium.org>
Date: Thu Dec 28 17:29:58 2017

Remove constant duplication in presubmit test.

Makes presubmit test use an existing constant from PRESUBMIT.py.

Bug:  762461 
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I4fcfed6430f166390c9aa1fd24109d73e8709cc0
Reviewed-on: https://chromium-review.googlesource.com/845620
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526301}
[modify] https://crrev.com/d7eac5cca81d054abf2ebd76919a4d3fb43e3d94/ios/PRESUBMIT_test.py