Take care not to destroy a multi-selection when a child element of a list item receives focus.

chrome/browser/resources/options/deletable_item_list.js

Index: chrome/browser/resources/options/deletable_item_list.js
diff --git a/chrome/browser/resources/options/deletable_item_list.js b/chrome/browser/resources/options/deletable_item_list.js
index d625dc5a7ca705e0e27b6957a40019c28818e22a..2fbf9984534800f12d624ab95c569eed3498b862 100644
--- a/chrome/browser/resources/options/deletable_item_list.js
+++ b/chrome/browser/resources/options/deletable_item_list.js
@@ -92,6 +92,13 @@ cr.define('options', function() {
      * @private
      */
     handleFocus_: function() {
+      // This handler is also fired when the child receives focus as a result of
+      // the item getting selected by the customized mouse/keyboard handling in
+      // SelectionController. Take care not to destroy a potential multiple
+      // selection in this case.
+      if (this.selected)
+        return;
+
       var list = this.parentNode;
       var index = list.getIndexOfListItem(this);
       list.selectionModel.selectedIndex = index;