MD Settings: fix unnecessary focus on list items.

chrome/browser/resources/settings/focusable_iron_list_item_behavior.js

Index: chrome/browser/resources/settings/focusable_iron_list_item_behavior.js
diff --git a/chrome/browser/resources/settings/focusable_iron_list_item_behavior.js b/chrome/browser/resources/settings/focusable_iron_list_item_behavior.js
index 997217725eff9085ef543e0f71eba81e2062a6d6..20e58c5b7db3efe8ef953cdc7253e5ea82a0e0e5 100644
--- a/chrome/browser/resources/settings/focusable_iron_list_item_behavior.js
+++ b/chrome/browser/resources/settings/focusable_iron_list_item_behavior.js
@@ -29,10 +29,15 @@ var FocusableIronListItemBehavior = {
 
   /**
    * Unflag when moving away via keyboard (e.g. tabbing onto its children).
+   * @param {!Event} event
    * @private
    */
-  onKeyDown_: function() {
+  onKeyDown_: function(event) {
     this.focusedByKey_ = false;
+
+    // For these types of items, don't propagate enter to iron-list's listener.
+    if (event.key == 'Enter')
+      event.stopPropagation();
   },
 
   /**