Add Feature Flag for UnifiedMessageCenter Refactor

This feature flag will enable a separate widget for the UnifiedMessageCenter.

Bug: 95802
Change-Id: I5b60ab5272e9ca3c444bfdf142059c2a5795217f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1719470Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681393}

ash/public/cpp/ash_features.cc

@@ -87,6 +87,9 @@ const base::Feature kSystemTrayFeaturePodsPagination{
 const base::Feature kSwapSideVolumeButtonsForOrientation{
     "SwapSideVolumeButtonsForOrientation", base::FEATURE_ENABLED_BY_DEFAULT};
 
+const base::Feature kUnifiedMessageCenterRefactor{
+    "UnifiedMessageCenterRefactor", base::FEATURE_DISABLED_BY_DEFAULT};
+
 bool IsHideArcMediaNotificationsEnabled() {
   return base::FeatureList::IsEnabled(kMediaSessionNotification) &&
          base::FeatureList::IsEnabled(kHideArcMediaNotifications);
@@ -156,5 +159,9 @@ bool IsSwapSideVolumeButtonsForOrientationEnabled() {
   return base::FeatureList::IsEnabled(kSwapSideVolumeButtonsForOrientation);
 }
 
+bool IsUnifiedMessageCenterRefactorEnabled() {
+  return base::FeatureList::IsEnabled(kUnifiedMessageCenterRefactor);
+}
+
 }  // namespace features
 }  // namespace ash

ash/public/cpp/ash_features.h

@@ -107,6 +107,10 @@ ASH_PUBLIC_EXPORT extern const base::Feature kSystemTrayFeaturePodsPagination;
 ASH_PUBLIC_EXPORT extern const base::Feature
     kSwapSideVolumeButtonsForOrientation;
 
+// Enables refactored UnifiedMessageCenter which is completely separated from
+// the UnifiedSystemTrayView.
+ASH_PUBLIC_EXPORT extern const base::Feature kUnifiedMessageCenterRefactor;
+
 ASH_PUBLIC_EXPORT bool IsHideArcMediaNotificationsEnabled();
 
 ASH_PUBLIC_EXPORT bool IsKeyboardShortcutViewerAppEnabled();
@@ -139,6 +143,8 @@ ASH_PUBLIC_EXPORT bool IsSystemTrayFeaturePodsPaginationEnabled();
 
 ASH_PUBLIC_EXPORT bool IsSwapSideVolumeButtonsForOrientationEnabled();
 
+ASH_PUBLIC_EXPORT bool IsUnifiedMessageCenterRefactorEnabled();
+
 }  // namespace features
 }  // namespace ash