PRESUBMIT check to keep gpu_workaround_list.txt sorted

Bug: 1038671
Change-Id: Ifb1fed6c3cca7badf85df8df92b1afbdf83bb614
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2020529
Auto-Submit: Fritz Koenig <frkoenig@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735164}

gpu/config/PRESUBMIT.py

+# Copyright (c) 2020 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.
+
+"""Enforces workaround list is alphabetically sorted.
+
+See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
+for more details on the presubmit API built into depot_tools.
+"""
+
+import difflib
+import os.path
+
+def _CheckGPUWorkaroundListSorted(input_api, output_api):
+    """Check: gpu_workaround_list.txt feature list sorted alphabetically.
+    """
+    filename = os.path.join(input_api.PresubmitLocalPath(),
+                            'gpu_workaround_list.txt')
+
+    workaround_list = [line.rstrip('\n') for line in open(filename)]
+
+    workaround_list_sorted = sorted(workaround_list, key=lambda s: s.lower())
+    if workaround_list == workaround_list_sorted:
+        return []
+    # Diff the sorted/unsorted versions.
+    differ = difflib.Differ()
+    diff = differ.compare(workaround_list, workaround_list_sorted)
+    return [output_api.PresubmitError(
+        'gpu_workaround_list.txt features must be sorted alphabetically. '
+        'Diff of feature order follows:', long_text='\n'.join(diff))]
+
+def CheckChangeOnUpload(input_api, output_api):
+  return _CheckGPUWorkaroundListSorted(input_api, output_api)
+
+def CheckChangeOnCommit(input_api, output_api):
+  return _CheckGPUWorkaroundListSorted(input_api, output_api)