Adding flag for material U popup

Test: compile
Bug: 247880037
Change-Id: I989fe88e070f5fe14494aa2c3d00071259907472
diff --git a/src/com/android/launcher3/config/FeatureFlags.java b/src/com/android/launcher3/config/FeatureFlags.java
index 0e36dc0..045391f 100644
--- a/src/com/android/launcher3/config/FeatureFlags.java
+++ b/src/com/android/launcher3/config/FeatureFlags.java
@@ -294,6 +294,9 @@
     public static final BooleanFlag ENABLE_WIDGET_PICKER_DEPTH = new DeviceFlag(
             "ENABLE_WIDGET_PICKER_DEPTH", true, "Enable changing depth in widget picker.");
 
+    public static final BooleanFlag POPUP_MATERIAL_U = new DeviceFlag(
+            "POPUP_MATERIAL_U", false, "Switch popup UX to use material U");
+
     public static void initialize(Context context) {
         synchronized (sDebugFlags) {
             for (DebugFlag flag : sDebugFlags) {