Show prelogin only once

 Bug: 5081641

Change-Id: I1c625e3528de9a7cd37dae5b8b428ff141759e14
diff --git a/res/values/strings.xml b/res/values/strings.xml
index a33670a..ee3ce95 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -591,6 +591,8 @@
         <item>5</item>
     </string-array>
     <string name="pref_development_error_console" translatable="false">Show JavaScript Console</string>
+    <!-- Do not translate. Development option to reset the prologin time [CHAR LIMIT=20] -->
+    <string name="pref_development_reset_prelogin" translatable="false">Reset prelogin</string>
     <!-- Settings screen, setting option name -->
     <string name="pref_default_text_encoding">Text encoding</string>
     <!-- Options in the Default encoding dialog box -->
diff --git a/res/xml/debug_preferences.xml b/res/xml/debug_preferences.xml
index 5126b0d..1fc4f4c 100644
--- a/res/xml/debug_preferences.xml
+++ b/res/xml/debug_preferences.xml
@@ -76,4 +76,8 @@
         android:title="@string/js_engine_flags"
         android:singleLine="true" />
 
+    <Preference
+        android:key="reset_prelogin"
+        android:title="@string/pref_development_reset_prelogin" />
+
 </PreferenceScreen>