Add Feature Flag for Hearing Aid Profile

Using the Settings App-Developer Options-Feature Flag, allow the user to
enable or disable the Hearing Aid Profile.

Bug: 116317072
Bug: 116044083
Test: Manual testing using Settings App
Change-Id: I58a9d339941e235242c443c85b6f4194b5a296c9
Merged-In: I58a9d339941e235242c443c85b6f4194b5a296c9
(cherry picked from commit fe8c8337edc5e9d6b61d0942873538912d523db7)
diff --git a/services/core/java/com/android/server/BluetoothManagerService.java b/services/core/java/com/android/server/BluetoothManagerService.java
index 99e0056..49de4b1 100644
--- a/services/core/java/com/android/server/BluetoothManagerService.java
+++ b/services/core/java/com/android/server/BluetoothManagerService.java
@@ -53,12 +53,16 @@
 import android.os.RemoteCallbackList;
 import android.os.RemoteException;
 import android.os.SystemClock;
+import android.os.SystemProperties;
 import android.os.UserHandle;
 import android.os.UserManager;
 import android.os.UserManagerInternal;
 import android.os.UserManagerInternal.UserRestrictionsListener;
 import android.provider.Settings;
 import android.provider.Settings.SettingNotFoundException;
+import android.text.TextUtils;
+import android.util.FeatureFlagUtils;
+import android.util.Log;
 import android.util.Slog;
 import android.util.StatsLog;
 
@@ -386,6 +390,15 @@
         mCallbacks = new RemoteCallbackList<IBluetoothManagerCallback>();
         mStateChangeCallbacks = new RemoteCallbackList<IBluetoothStateChangeCallback>();
 
+        // TODO: We need a more generic way to initialize the persist keys of FeatureFlagUtils
+        boolean isHearingAidEnabled;
+        String value = SystemProperties.get(FeatureFlagUtils.PERSIST_PREFIX + FeatureFlagUtils.HEARING_AID_SETTINGS);
+        if (!TextUtils.isEmpty(value)) {
+            isHearingAidEnabled = Boolean.parseBoolean(value);
+            Log.v(TAG, "set feature flag HEARING_AID_SETTINGS to " + isHearingAidEnabled);
+            FeatureFlagUtils.setEnabled(context, FeatureFlagUtils.HEARING_AID_SETTINGS, isHearingAidEnabled);
+        }
+
         IntentFilter filter = new IntentFilter();
         filter.addAction(BluetoothAdapter.ACTION_LOCAL_NAME_CHANGED);
         filter.addAction(BluetoothAdapter.ACTION_BLUETOOTH_ADDRESS_CHANGED);