Allow use of ScopedAllowIO in browser tests

PRESUBMIT.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
@@ skipping 173 matching lines @@
       True,
       (
         r"^ui[\\\/]gl[\\\/].*\.cc$",
         r"^media[\\\/]gpu[\\\/].*\.cc$",
         r"^gpu[\\\/].*\.cc$",
       ),
     ),
     (
       'ScopedAllowIO',
       (
-       'New code should not use ScopedAllowIO. Post a task to the blocking',
-       'pool or the FILE thread instead.',
+       'New production code should not use ScopedAllowIO (using it in',
+       'browser tests is fine). Post a task to the blocking pool or the',
+       'FILE thread instead.',
       ),
       True,
       (
+        r"^.*browser(|_)test[a-z_]*\.cc$",

[satorux1, 2017/05/30 04:33:20]

This pattern is based on the existing pattern

  r"^content[\\\/].*browser(|_)test[a-zA-Z_]*\.cc$",

but removed A-Z since it does not make a difference.

[Matt Giuca, 2017/05/30 05:35:56]

Could we extend this to all files with "test" in the name (drop "browser")? This
affects unit tests too (my original case was TestingProfile which is used by
unit tests).

[Matt Giuca, 2017/05/30 05:48:01]

I guess there's no point in allowing it currently if nobody is using it.

I thought unit tests needed it because they have no threads; therefore if they
run normally-multithreaded code on one thread they have to use ScopedAllowIO.
They do indirectly use it through TestingProfile but maybe that's it.

         r"^base[\\\/]memory[\\\/]shared_memory_posix\.cc$",
         r"^base[\\\/]process[\\\/]internal_aix\.cc$",
         r"^base[\\\/]process[\\\/]process_linux\.cc$",
         r"^base[\\\/]process[\\\/]process_metrics_linux\.cc$",
         r"^chrome[\\\/]browser[\\\/]chromeos[\\\/]boot_times_recorder\.cc$",
         r"^chrome[\\\/]browser[\\\/]lifetime[\\\/]application_lifetime\.cc$",
-        r"^chrome[\\\/]browser[\\\/]chromeos[\\\/]"
-            "customization_document_browsertest\.cc$",
         r"^components[\\\/]crash[\\\/]app[\\\/]breakpad_mac\.mm$",
         r"^content[\\\/]shell[\\\/]browser[\\\/]layout_test[\\\/]" +
             r"test_info_extractor\.cc$",
-        r"^content[\\\/].*browser(|_)test[a-zA-Z_]*\.cc$",
         r"^content[\\\/]shell[\\\/]browser[\\\/]shell_browser_main\.cc$",
         r"^content[\\\/]shell[\\\/]browser[\\\/]shell_message_filter\.cc$",
         r"^content[\\\/]test[\\\/]ppapi[\\\/]ppapi_test\.cc$",
         r"^mojo[\\\/]edk[\\\/]embedder[\\\/]" +
             r"simple_platform_shared_buffer_posix\.cc$",
         r"^net[\\\/]disk_cache[\\\/]cache_util\.cc$",
         r"^net[\\\/]cert[\\\/]test_root_certs\.cc$",
         r"^net[\\\/]test[\\\/]embedded_test_server[\\\/]" +
             r"embedded_test_server\.cc$",
         r"^net[\\\/]test[\\\/]spawned_test_server[\\\/]local_test_server\.cc$",
@@ skipping 2243 matching lines @@
       output_api,
       json_url='http://chromium-status.appspot.com/current?format=json'))
 
   results.extend(
       input_api.canned_checks.CheckPatchFormatted(input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasBugField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   return results