Add a stylus controller to Bluetooth Device Details.

In this CL stylus preferences will show for every type of input device.
Feature is currently flagged behing SETTINGS_SHOW_STYLUS_PREFERENCES.

Bug: b/251201006
Test: SettingsRoboTests StylusDevicesControllerTest
DD: go/stylus-connected-devices-doc
Change-Id: I73cec8e5cfd0b70be0492841f9d8e07f62a70863
diff --git a/core/java/android/util/FeatureFlagUtils.java b/core/java/android/util/FeatureFlagUtils.java
index 4afd268..bd0e3c9 100644
--- a/core/java/android/util/FeatureFlagUtils.java
+++ b/core/java/android/util/FeatureFlagUtils.java
@@ -133,6 +133,13 @@
     public static final String SETTINGS_ADB_METRICS_WRITER = "settings_adb_metrics_writer";
 
     /**
+     * Flag to show stylus-specific preferences in Connected Devices
+     * @hide
+     */
+    public static final String SETTINGS_SHOW_STYLUS_PREFERENCES =
+            "settings_show_stylus_preferences";
+
+    /**
      * Flag to enable/disable biometrics enrollment v2
      * @hide
      */
@@ -173,10 +180,12 @@
         DEFAULT_FLAGS.put(SETTINGS_NEW_KEYBOARD_TRACKPAD, "false");
         DEFAULT_FLAGS.put(SETTINGS_ENABLE_SPA, "false");
         DEFAULT_FLAGS.put(SETTINGS_ADB_METRICS_WRITER, "false");
+        DEFAULT_FLAGS.put(SETTINGS_SHOW_STYLUS_PREFERENCES, "false");
         DEFAULT_FLAGS.put(SETTINGS_BIOMETRICS2_ENROLLMENT, "false");
     }
 
     private static final Set<String> PERSISTENT_FLAGS;
+
     static {
         PERSISTENT_FLAGS = new HashSet<>();
         PERSISTENT_FLAGS.add(SETTINGS_ALLOW_INTENT_REDIRECTION_FOR_CLONE_PROFILE);