Add demo mode to dev options

Change-Id: I8c12dc55aef99b54d8d12f7d34e69ca77408f5b2
Fixes: 27919212
diff --git a/res/values/strings.xml b/res/values/strings.xml
index ffcba69..834d136 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -7375,4 +7375,7 @@
     <!-- [CHAR LIMIT=25] Bluetooth is disabled. -->
     <string name="bluetooth_disabled">Disabled</string>
 
+    <!-- [CHAR LIMIT=60] Name of dev option called demo mode -->
+    <string name="demo_mode">Demo mode</string>
+
 </resources>
diff --git a/res/xml/development_prefs.xml b/res/xml/development_prefs.xml
index 7415464..e737ba8 100644
--- a/res/xml/development_prefs.xml
+++ b/res/xml/development_prefs.xml
@@ -91,6 +91,12 @@
         android:key="ota_disable_automatic_update"
         android:title="@string/ota_disable_automatic_update" />
 
+    <PreferenceScreen
+        android:key="demo_mode"
+        android:title="@string/demo_mode">
+        <intent android:action="com.android.settings.action.DEMO_MODE" />
+    </PreferenceScreen>
+
     <PreferenceCategory android:key="debug_debugging_category"
             android:title="@string/debug_debugging_category">