MD Settings: Bluetooth: Add error dialog and messages

chrome/test/data/webui/i18n_behavior_test.html

Index: chrome/test/data/webui/i18n_behavior_test.html
diff --git a/chrome/test/data/webui/i18n_behavior_test.html b/chrome/test/data/webui/i18n_behavior_test.html
index 3dd199a37b543fea0ea4656dfba46ecb2b3a804b..0bd41fd844a132997550f218ad2cce148c25ec27 100644
--- a/chrome/test/data/webui/i18n_behavior_test.html
+++ b/chrome/test/data/webui/i18n_behavior_test.html
@@ -35,6 +35,11 @@ function testI18nAdvanced() {
   I18nBehavior.i18nAdvanced('customTag', {tags: ['X-FOO']});
 }
 
+function testI18nExists() {
+  assertTrue(I18nBehavior.i18nExists('text'));
+  assertFalse(I18nBehavior.i18nExists('missingText'));
+}
+ 
 </script>
 </body>
 </html>