Demote linux-386 to "best effort support", just like e.g. linux-ppc64.

It seems unfair to completely kill linux-386, while we still provide minimal
best-effort support for more exotic platforms like linux-ppc64 or linux-s390x.

R=iannucci@chromium.org, tandrii@chromium.org
BUG=854300

Change-Id: Ia31ebb42f7e596c495b09bb99ecb376801256d55
Reviewed-on: https://chromium-review.googlesource.com/1111026Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>

PRESUBMIT.py

@@ -12,11 +12,13 @@ import fnmatch
 import os
 
 
-ENSURE_FILE_TEMPLATE = r'''
-$VerifiedPlatform linux-amd64 linux-arm64 linux-armv6l linux-mips64
-$VerifiedPlatform linux-ppc64 linux-ppc64le linux-s390x
-$VerifiedPlatform mac-amd64
-$VerifiedPlatform windows-386 windows-amd64
+# CIPD ensure manifest for checking CIPD client itself.
+CIPD_CLIENT_ENSURE_FILE_TEMPLATE = r'''
+# Full supported.
+$VerifiedPlatform linux-amd64 mac-amd64 windows-amd64 windows-386
+# Best effort support.
+$VerifiedPlatform linux-386 linux-ppc64 linux-ppc64le linux-s390x
+$VerifiedPlatform linux-arm64 linux-armv6l linux-mips64
 
 %s %s
 '''
@@ -97,7 +99,8 @@ def CommonChecks(input_api, output_api, tests_to_black_list):
       pkg = 'infra/tools/cipd/${platform}'
       ver = input_api.ReadFile(path)
       tests.append(input_api.canned_checks.CheckCIPDManifest(
-          input_api, output_api, content=ENSURE_FILE_TEMPLATE % (pkg, ver)))
+          input_api, output_api,
+          content=CIPD_CLIENT_ENSURE_FILE_TEMPLATE % (pkg, ver)))
 
   results.extend(input_api.RunTests(tests))
   return results

cipd_manifest.txt

@@ -2,10 +2,14 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-$VerifiedPlatform linux-amd64 linux-arm64 linux-armv6l linux-mips64
-$VerifiedPlatform linux-ppc64 linux-ppc64le linux-s390x
-$VerifiedPlatform mac-amd64
-$VerifiedPlatform windows-386 windows-amd64
+# Fully supported plaforms.
+$VerifiedPlatform linux-amd64 mac-amd64 windows-amd64 windows-386
+
+# Platform with best-effort support: we have some binaries cross-compiled for
+# them, but we do not test they work. They also may not have all necessary
+# vpython packages.
+$VerifiedPlatform linux-386 linux-ppc64 linux-ppc64le linux-s390x
+$VerifiedPlatform linux-arm64 linux-armv6l linux-mips64
 
 # vpython.
 infra/tools/luci/vpython/${platform}  git_revision:4d19637ec2c3d1efd8c6a1b05285118b786919e2