MD Settings: Listen to the Enter key in the Add User ChromeOS dialog.

chrome/browser/resources/settings/people_page/users_add_user_dialog.js

Index: chrome/browser/resources/settings/people_page/users_add_user_dialog.js
diff --git a/chrome/browser/resources/settings/people_page/users_add_user_dialog.js b/chrome/browser/resources/settings/people_page/users_add_user_dialog.js
index 2bc985478053acf365333c18b943d9021623deef..b1383ee9516280b2881e0e9f6cc00562bc85b9ab 100644
--- a/chrome/browser/resources/settings/people_page/users_add_user_dialog.js
+++ b/chrome/browser/resources/settings/people_page/users_add_user_dialog.js
@@ -57,7 +57,9 @@ Polymer({
 
   /** @private */
   addUser_: function() {
-    assert(this.validate_());
+    // May be submitted by the Enter key even if the input value is invalid.
+    if (!this.validate_())
+      return;
 
     var input = this.$.addUserInput.value;