Fixup WebSchedulerTrackedFeature Enum

Recently updating the WebSchedulerTrackedFeature histogram enum it was
noticed that the current labels are out of sync. This change adds a new
presubmit check to help warn committers to keep the value up to date.
In addition the current labels have been updated to reflect the current
in-code values being reported.

Change-Id: I8e3fb6dd452454f4efa0aecf65348bcce4517c6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2063359Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Brandon Maslen <brandm@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#742822}

third_party/blink/public/common/scheduler/PRESUBMIT.py

+# Copyright 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.
+"""Blink feature-policy presubmit script.
+
+See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
+for more details about the presubmit API built into gcl.
+"""
+
+
+def _RunUmaHistogramChecks(input_api, output_api):  # pylint: disable=C0103
+    import sys
+
+    original_sys_path = sys.path
+    try:
+        sys.path = sys.path + [input_api.os_path.join(
+            input_api.PresubmitLocalPath(), '..', '..', '..', '..', '..',
+            'tools', 'metrics', 'histograms')]
+        import update_histogram_enum  # pylint: disable=F0401
+    finally:
+        sys.path = original_sys_path
+
+    source_path = ''
+    for f in input_api.AffectedFiles():
+        if f.LocalPath().endswith('web_scheduler_tracked_feature.h'):
+            source_path = f.LocalPath()
+            break
+    else:
+        return []
+
+    start_marker = '^enum class WebSchedulerTrackedFeature {'
+    end_marker = '^kMaxValue'
+    presubmit_error = update_histogram_enum.CheckPresubmitErrors(
+        histogram_enum_name='WebSchedulerTrackedFeature',
+        update_script_name='update_scheduler_enums.py',
+        source_enum_path=source_path,
+        start_marker=start_marker,
+        end_marker=end_marker,
+        strip_k_prefix=True)
+    if presubmit_error:
+        return [output_api.PresubmitPromptWarning(presubmit_error,
+                                                  items=[source_path])]
+    return []
+
+
+def CheckChangeOnUpload(input_api, output_api):  # pylint: disable=C0103
+    results = []
+    results.extend(_RunUmaHistogramChecks(input_api, output_api))
+    return results
+
+
+def CheckChangeOnCommit(input_api, output_api):  # pylint: disable=C0103
+    results = []
+    results.extend(_RunUmaHistogramChecks(input_api, output_api))
+    return results

tools/metrics/histograms/enums.xml

@@ -67812,6 +67812,8 @@ Full version information for the fingerprint enum values:
 </enum>
 
 <enum name="WebSchedulerTrackedFeature">
+<!-- Generated from third_party/blink/public/common/scheduler/web_scheduler_tracked_feature.h.-->
+
   <int value="0" label="WebSocket"/>
   <int value="1" label="WebRTC"/>
   <int value="2" label="MainResourceHasCacheControlNoCache"/>
@@ -67836,15 +67838,19 @@ Full version information for the fingerprint enum values:
   <int value="21" label="RequestedMIDIPermission"/>
   <int value="22" label="RequestedAudioCapturePermission"/>
   <int value="23" label="RequestedVideoCapturePermission"/>
-  <int value="24" label="RequestedSensorsPermission"/>
-  <int value="25" label="RequestedBackgroundWorkPermission"/>
-  <int value="26" label="BroadcastChannel"/>
-  <int value="27" label="IndexedDBConnection"/>
-  <int value="28" label="WebGL"/>
-  <int value="29" label="WebVR"/>
-  <int value="30" label="WebXR"/>
-  <int value="31" label="SharedWorker"/>
-  <int value="32" label="WebLocks"/>
+  <int value="24" label="RequestedBackForwardCacheBlockedSensors"/>
+  <int value="25" label="Unused"/>
+  <int value="26" label="RequestedBackgroundWorkPermission"/>
+  <int value="27" label="BroadcastChannel"/>
+  <int value="28" label="IndexedDBConnection"/>
+  <int value="29" label="WebGL"/>
+  <int value="30" label="WebVR"/>
+  <int value="31" label="WebXR"/>
+  <int value="32" label="SharedWorker"/>
+  <int value="33" label="WebLocks"/>
+  <int value="34" label="WebHID"/>
+  <int value="35" label="WakeLock"/>
+  <int value="36" label="WebShare"/>
   <int value="37" label="RequestedStorageAccessGrant"/>
 </enum>
 

tools/metrics/histograms/update_scheduler_enums.py

+#!/usr/bin/env python
+# Copyright 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.
+"""Updates the WebSchedulerTrackedFeature enum in enums.xml file with
+values read from web_scheduler_tracked_feature.h.
+
+If the file was pretty-printed, the updated version is pretty-printed too.
+"""
+
+from __future__ import print_function
+
+import os
+import sys
+
+from update_histogram_enum import UpdateHistogramEnum
+
+if __name__ == '__main__':
+  if len(sys.argv) > 1:
+    print('No arguments expected!', file=sys.stderr)
+    sys.stderr.write(__doc__)
+    sys.exit(1)
+
+  source_file = 'third_party/blink/public/common/scheduler/' \
+                'web_scheduler_tracked_feature.h'
+  UpdateHistogramEnum(
+      histogram_enum_name='WebSchedulerTrackedFeature',
+      source_enum_path=source_file,
+      start_marker='^enum class WebSchedulerTrackedFeature {',
+      end_marker='^kMaxValue',
+      strip_k_prefix=True)