Switch autologin to ListPreference

 Bug: 3365170
 Switch the autologin preference to use a ListPreference instead of
 a checkbox preference that would open a dialog when enabled.

Change-Id: I29230a4e7663593b126e89efb50ecef37d46e808
diff --git a/res/xml/privacy_security_preferences.xml b/res/xml/privacy_security_preferences.xml
index 54f3ff0..9bff4b8 100644
--- a/res/xml/privacy_security_preferences.xml
+++ b/res/xml/privacy_security_preferences.xml
@@ -39,10 +39,9 @@
             android:title="@string/pref_security_show_security_warning"
             android:summary="@string/pref_security_show_security_warning_summary" />
 
-    <CheckBoxPreference
-            android:key="enable_autologin"
-            android:title="@string/pref_autologin_title"
-            android:defaultValue="true" />
+    <ListPreference
+            android:key="autologin_account"
+            android:title="@string/pref_autologin_title" />
 
     <PreferenceCategory android:title="@string/pref_privacy_cookies_title">
         <CheckBoxPreference