Fix regression where rows could become non-focusable.

ui/webui/resources/js/cr/ui/focus_grid.js

 // Copyright 2014 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('cr.ui', function() {
   /**
    * A class to manage grid of focusable elements in a 2D grid. For example,
    * given this grid:
    *
    *   focusable  [focused]  focusable  (row: 0, col: 1)
@@ skipping 121 matching lines @@
         this.ignoreFocusChange_ = false;
         return;
       }
 
       var target = assertInstanceof(e.target, Node);
       if (this.getRowIndexForTarget(target) != -1)
         this.lastFocused = target;
     },
 
     /**
-     * Add a FocusRow to this grid. This needs to be called AFTER adding columns
-     * to the row. This is so that TAB focus can be properly enabled in the
-     * columns.
+     * Add a FocusRow to this grid. Row is added at the end.

[Dan Beam, 2015/05/12 01:28:42]

Adds |row| to the end of this grid.

[hcarmona, 2015/05/12 02:00:47]

Done.

      * @param {cr.ui.FocusRow} row The row that needs to be added to this grid.
      */
     addRow: function(row) {
-      row.delegate = row.delegate || this.delegate_;
-      this.rows.push(row);
+      this.addRowBefore(row, null);
     },
 
     /**
+     * Add a FocusRow to this grid in order. Adds at the end if |nextRow| is

[Dan Beam, 2015/05/12 01:28:42]

Add -> Adds

[hcarmona, 2015/05/12 02:00:47]

Done.

+     * not in the list of rows.
+     * @param {cr.ui.FocusRow} row The row that needs to be added to this grid.

[Dan Beam, 2015/05/12 01:28:42]

!cr.ui.FocusRow for |row|

[hcarmona, 2015/05/12 02:00:47]

Done.

+     * @param {cr.ui.FocusRow} nextRow The row that should follow |row|.
+     */
+    addRowBefore: function(row, nextRow) {
+      row.delegate = row.delegate || this.delegate_;
+
+      var nextRowIndex = this.rows.indexOf(nextRow);
+      if (nextRowIndex == -1) {

[Dan Beam, 2015/05/12 01:28:42]

no curlies

[hcarmona, 2015/05/12 02:00:47]

Done.

+        this.rows.push(row);
+      } else {
+        this.rows.splice(nextRowIndex, 0, row);
+      }
+    },
+
+    /**
+     * Removes a row from the focus row. No-op if row is not in the grid.
+     * @param {cr.ui.FocusRow} row The row that needs to be removed.
+     */
+    removeRow: function(row) {
+      var nextRowIndex = this.rows.indexOf(row);
+      if (nextRowIndex > -1) {

[Dan Beam, 2015/05/12 01:28:42]

no curlies

[hcarmona, 2015/05/12 02:00:47]

Done.

+        this.rows.splice(nextRowIndex, 1);
+      }
+    },
+
+    /**
      * Makes sure that at least one row is active. Should be called once, after
      * adding all rows to FocusGrid.
      */
     ensureRowActive: function() {
       if (this.rows.length == 0)
         return;
 
       for (var i = 0; i < this.rows.length; ++i) {
         if (this.rows[i].isActive())
           return;
       }
 
       this.rows[0].makeActive(true);
     },
   };
 
   return {
     FocusGrid: FocusGrid,
   };
 });