[Chrome Settings UI] If User Exceptions are not allowed, prevent editing / viewing.

chrome/browser/resources/options/content_settings_exceptions_area.js

 // Copyright (c) 2012 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.contentSettings', function() {
   /** @const */ var ControlledSettingIndicator =
                     options.ControlledSettingIndicator;
   /** @const */ var InlineEditableItemList = options.InlineEditableItemList;
   /** @const */ var InlineEditableItem = options.InlineEditableItem;
   /** @const */ var ArrayDataModel = cr.ui.ArrayDataModel;
@@ skipping 502 matching lines @@
                                       entry);
       } else {
         var addRowItem = new ExceptionsAddRowListItem(this.contentType,
                                                       this.mode);
         addRowItem.deletable = false;
         return addRowItem;
       }
     },
 
     /**
+     * Updates visibility of each row, depending on content.
+     */
+    updateRowVisibility: function() {
+      // Rows with user exceptions are visible iff this.isEditable().
+      // All other rows are visible.
+      var isEditable = this.isEditable();
+      for (var index = 0; index < this.dataModel.length; ++index) {
+        var item = this.getListItemByIndex(index);
+        if (item.dataItem.source == 'preference')
+          item.hidden = !isEditable;
+      }
+    },
+
+    /**
+     * Sets whether user is allowed to set preference exceptions. Updates UI.
+     *
+     * @param {string} allowEdit Whether or not user may set preference
+     *    exceptions.
+     */
+    setAllowEdit: function(allowEdit) {
+      var oldIsEditable = this.isEditable();
+      this.allowEdit = allowEdit;
+      var newIsEditable = this.isEditable();
+
+      // If visibility changed, add or remove the Add New Exception row.
+      if (oldIsEditable != newIsEditable) {
+        var oldSize = this.dataModel.length;
+        if (newIsEditable) {
+          this.dataModel.push(null);
+        } else {
+          this.dataModel.splice(oldSize - 1, 1);  // pop.

[Evan Stade, 2016/04/26 16:05:16]

I would be in favor of adding pop to ArrayDataModel

[huangs, 2016/04/26 17:37:03]

ArrayDataModel stores raw list of data in |this.array_|, and the elements are
ordered by |this.indexes_|, sorting is applied to this order.  If we add pop()
then it will remove the "logical last element", i.e.,
this.array_[this.index_[this.index_.length - 1]]?

Meanwhile, it looks like ExceptionList is skipping all this sorting business
because |this.dataModel.sortStatus_.field| == null.  Rather than adding a more
general pop() that only we use, and without exercising its generality, I think
it's cleaner to just call splice() explicitly?

[Evan Stade, 2016/04/26 22:58:09]

Don't you think pop() would be useful in other places? It's likely that the only
reason it's not used anywhere else currently is because it doesn't exist and
everyone just keeps using splice.

[huangs, 2016/04/26 23:18:20]

My preference is to keep the CL small.  It seems adding pop() and refactoring
users for it should be an independent cleanup?  +dbeam@ for discussion.

[Dan Beam, 2016/04/27 02:29:39]

i don't really know much about ArrayDataModel, but could we just add pop() as an
alias for splice(this.length - 1, 1) basically with a TODO?

[huangs, 2016/04/27 14:28:01]

Added pop(). It returns the last item as well, for least surprise.

+        }
+      }
+      this.updateRowVisibility();
+    },
+
+    /**
      * Sets the exceptions in the js model.
      *
      * @param {Array<options.Exception>} entries A list of dictionaries of
      *     values, each dictionary represents an exception.
      */
     setExceptions: function(entries) {
       var deleteCount = this.dataModel.length;
 
       if (this.isEditable()) {
         // We don't want to remove the Add New Exception row.
         deleteCount = deleteCount - 1;
       }
 
       var args = [0, deleteCount];
       args.push.apply(args, entries);
       this.dataModel.splice.apply(this.dataModel, args);
+      this.updateRowVisibility();
     },
 
     /**
      * The browser has finished checking a pattern for validity. Update the list
      * item to reflect this.
      *
      * @param {string} pattern The pattern.
      * @param {boolean} valid Whether said pattern is valid in the context of a
      *     content exception setting.
      */
     patternValidityCheckComplete: function(pattern, valid) {
       var listItems = this.items;
       for (var i = 0; i < listItems.length; i++) {
         var listItem = listItems[i];
         // Don't do anything for messages for the item if it is not the intended
         // recipient, or if the response is stale (i.e. the input value has
         // changed since we sent the request to analyze it).
         if (pattern == listItem.input.value)
           listItem.setPatternValid(valid);
       }
     },
 
     /**
      * Returns whether the rows are editable in this list.
      */
     isEditable: function() {
-      // Exceptions of the following lists are not editable for now.
-      return isEditableType(this.contentType);
+      return this.allowEdit && isEditableType(this.contentType);
     },
 
     /**
      * Removes all exceptions from the js model.
      */
     reset: function() {
+      this.allowEdit = true;
       if (this.isEditable()) {
         // The null creates the Add New Exception row.
         this.dataModel = new ArrayDataModel([null]);
       } else {
         this.dataModel = new ArrayDataModel([]);
       }
     },
 
     /** @override */
     deleteItemAtIndex: function(index) {
@@ skipping 113 matching lines @@
     }
   };
 
   return {
     ExceptionsListItem: ExceptionsListItem,
     ExceptionsAddRowListItem: ExceptionsAddRowListItem,
     ExceptionsList: ExceptionsList,
     ContentSettingsExceptionsArea: ContentSettingsExceptionsArea,
   };
 });