cros: Use runtime stylus detection for ash palette.

chrome/test/data/webui/settings/device_page_tests.js

Index: chrome/test/data/webui/settings/device_page_tests.js
diff --git a/chrome/test/data/webui/settings/device_page_tests.js b/chrome/test/data/webui/settings/device_page_tests.js
index b5619b792445798e1845edc3d67890c63bf5e6ee..c953240b05a07849a71cddb9c844d9b18353fbfe 100644
--- a/chrome/test/data/webui/settings/device_page_tests.js
+++ b/chrome/test/data/webui/settings/device_page_tests.js
@@ -33,6 +33,12 @@ cr.define('device_page_tests', function() {
       cr.webUIListenerCallback('has-touchpad-changed', true);
     },
 
+    /** override */
+    initializeStylus: function() {
+      // Enable stylus.
+      cr.webUIListenerCallback('has-stylus-changed', true);
+    },
+
     /** @override */
     handleLinkEvent: function(e) {
       settings.DevicePageBrowserProxyImpl.prototype.handleLinkEvent.call(