Depend on support lib preferences

Bug: 24576551
Change-Id: Ic6190bacd3f7582c9bbc8de972da4612bd92421e
diff --git a/src/com/android/settings/UserCredentialsSettings.java b/src/com/android/settings/UserCredentialsSettings.java
index f10bb09..c440acf 100644
--- a/src/com/android/settings/UserCredentialsSettings.java
+++ b/src/com/android/settings/UserCredentialsSettings.java
@@ -17,8 +17,6 @@
 package com.android.settings;
 
 import android.app.AlertDialog;
-import android.app.Dialog;
-import android.app.Fragment;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.os.AsyncTask;
@@ -28,23 +26,20 @@
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.Adapter;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.ArrayAdapter;
 import android.widget.ListAdapter;
-import android.widget.Button;
 import android.widget.ListView;
 import android.widget.TextView;
 
 import java.util.EnumSet;
-import java.util.List;
 import java.util.Set;
 import java.util.SortedMap;
 import java.util.TreeMap;
 
-import static android.view.View.VISIBLE;
 import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
 
 public class UserCredentialsSettings extends InstrumentedFragment implements OnItemClickListener {
     private static final String TAG = "UserCredentialsSettings";