Fix behaviors of Add and Remove buttons.

chrome/browser/resources/options/chromeos_language_list.js

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('options.language', function() {
   const List = cr.ui.List;
   const ListItem = cr.ui.ListItem;
   const ArrayDataModel = cr.ui.ArrayDataModel;
   const LanguageOptions = options.LanguageOptions;
 
@@ skipping 44 matching lines @@
       var languageDisplayName =
           LanguageList.getDisplayNameFromLanguageCode(languageCode);
       return new ListItem({label: languageDisplayName});
     },
 
     /*
      * Adds a language to the language list.
      * @param {string} languageCode language code (ex. "fr").
      */
     addLanguage: function(languageCode) {
-      var dataModel = this.dataModel;
-      dataModel.push(languageCode);
+      this.dataModel.push(languageCode);
+      // Select the last item, which is the language added.
+      this.selectionModel.selectedIndex = this.dataModel.length - 1;

[arv (Not doing code reviews), 2010/08/04 17:19:54]

You might want to set leadIndex and anchorIndex as well or keyboard navigation
will act as the user expects.

[satorux1, 2010/08/05 04:12:50]

Thank you for pointing this out. We'll be supposedly switching to a single
selection model in the options page, so I would not add code for leadIndex and
anchorIndex here for now.

 
       this.updateBackend_();
     },
 
     /*
      * Gets the language codes of the currently listed languages.
      */
     getLanguageCodes: function() {
       return this.dataModel.slice();
     },
@@ skipping 17 matching lines @@
         // handle that case here.
         var originalIndex = this.selectionModel.selectedIndex;
         this.dataModel.splice(this.selectionModel.selectedIndex, 1);
         // Select the item at the original index if possible. Otherwise,
         // select the last item.
         // TODO(satorux): This should be handled by the selection model
         // See crbug.com/49893.
         this.selectionModel.selectedIndex = Math.min(
             originalIndex,
             this.dataModel.length - 1);
-        var newLanguageCodes = this.dataModel.slice();
-        this.load_(newLanguageCodes);
         this.updateBackend_();
       }
     },
 
     /**
      * Handles pref change.
      * @param {Event} e The change event object.
      * @private
      */
     handlePrefChange_: function(e) {
       var languageCodesInCsv = e.value;
       var languageCodes = this.filterBadLanguageCodes_(
           languageCodesInCsv.split(','));
       this.load_(languageCodes);
     },
 
     /**
      * Loads given language list.
      * @param {Array} languageCodes List of language codes.
      * @private
      */
     load_: function(languageCodes) {
+      // Preserve the original selected index. See comments below.
+      var originalSelectedIndex = (this.selectionModel ?
+                                   this.selectionModel.selectedIndex : -1);
       this.dataModel = new ArrayDataModel(languageCodes);
-      // Select the first item if it's not empty.
-      // TODO(satorux): Switch to a single item selection model that does
-      // not allow no selection, one it's ready: crbug.com/49893
-      if (this.dataModel.length > 0)
+      if (originalSelectedIndex >= 0 &&
+          originalSelectedIndex < this.dataModel.length) {
+        // Restore the original selected index if the selected index is
+        // valid after the data model is loaded. This is neeeded to keep
+        // the selected language after the languge is added or removed.
+        this.selectionModel.selectedIndex = originalSelectedIndex;
+      } else if (this.dataModel.length > 0){
+        // Otherwise, select the first item if it's not empty.
+        // TODO(satorux): Switch to a single item selection model that does
+        // not allow no selection, one it's ready: crbug.com/49893
         this.selectionModel.selectedIndex = 0;
+      }
     },
 
     /**
      * Updates backend.
      */
     updateBackend_: function() {
       // Encode the language codes into a CSV string.
       Preferences.setStringPref(this.pref, this.dataModel.slice().join(','));
     },
 
@@ skipping 13 matching lines @@
         }
       }
       return filteredLanguageCodes;
     },
   };
 
   return {
     LanguageList: LanguageList
   };
 });