Allow any committer to approve changes to field trial testing config.

This should reduce review latency/friction of making these changes.

Additionally, expanded the README to mention the GN build flag
fieldtrial_testing_like_official_build which can be used to disable
the testing config.

Bug: None
Change-Id: I5995bdf59a6a02640a7c9119830e0be1d3a33316
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537098Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Weilun Shi <sweilun@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833023}

testing/variations/OWNERS

 file://base/metrics/OWNERS
 
-# Temporarily listed here while training up as broader metrics owners.
-per-file fieldtrial_testing_config.json=caitlinfischer@google.com
-per-file fieldtrial_testing_config.json=sweilun@chromium.org
-
-# Use the following owners only if:
-#  - You work in the same area as them.
-#  - They are already aware of the field trial being modified.
-per-file fieldtrial_testing_config.json=tbansal@chromium.org
+# Changes to the testing config can be approved by any committer.
+per-file fieldtrial_testing_config.json=*
\ No newline at end of file

testing/variations/README.md

@@ -10,6 +10,10 @@ perf bots and browser tests in the waterfall.
 > Note: This configuration applies specifically to Chromium developer builds.
 > Chrome branded / official builds do not use these definitions.
 
+> Note: Non-developer builds of Chromium (for example, non-Chrome browsers,
+> or Chromium builds provided by Linux distros) should disable the testing
+> config via the GN flag `fieldtrial_testing_like_official_build=true`.
+
 > Note: This configuration is NOT used for content_browsertests or other test
 > targets based on content_shell.