Cros: Add event handler for shelf auto dim.

Bug: 996006
Change-Id: I2d819b32177ad10da1ad07b5f266a25f4f25d200
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1762936
Commit-Queue: Yulun Wu <[email protected]>
Reviewed-by: Ahmed Fakhry <[email protected]>
Reviewed-by: Alexander Alekseev <[email protected]>
Reviewed-by: Manu Cornet <[email protected]>
Reviewed-by: Toni Baržić <[email protected]>
Cr-Commit-Position: refs/heads/master@{#710944}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 35eccc9b..8082f855 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -4211,6 +4211,12 @@
      FEATURE_VALUE_TYPE(blink::features::kAudioWorkletRealtimeThread)},
 
 #if defined(OS_CHROMEOS)
+    {"dim-shelf", flag_descriptions::kShelfDimmingName,
+     flag_descriptions::kShelfDimmingDescription, kOsCrOS,
+     FEATURE_VALUE_TYPE(ash::features::kShelfDimming)},
+#endif  // defined(OS_CHROMEOS)
+
+#if defined(OS_CHROMEOS)
     {"release-notes", flag_descriptions::kReleaseNotesName,
      flag_descriptions::kReleaseNotesDescription, kOsCrOS,
      FEATURE_VALUE_TYPE(chromeos::features::kReleaseNotes)},