Fix build

Test: compile
Change-Id: I3d236ea1b1f5ee5b4b5b2aa118416383b5b4bb6d
diff --git a/src/com/android/settings/development/featureflags/FeatureFlagPersistent.java b/src/com/android/settings/development/featureflags/FeatureFlagPersistent.java
index 457b362..30d5cd7 100644
--- a/src/com/android/settings/development/featureflags/FeatureFlagPersistent.java
+++ b/src/com/android/settings/development/featureflags/FeatureFlagPersistent.java
@@ -18,11 +18,12 @@
 
 import android.content.Context;
 import android.os.SystemProperties;
-import android.support.annotation.VisibleForTesting;
 import android.text.TextUtils;
 import android.util.FeatureFlagUtils;
 import android.util.Log;
 
+import androidx.annotation.VisibleForTesting;
+
 import com.android.settings.core.FeatureFlags;
 
 import java.util.HashSet;