Fix regression where rows could become non-focusable.

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

Index: ui/webui/resources/js/cr/ui/focus_grid.js
diff --git a/ui/webui/resources/js/cr/ui/focus_grid.js b/ui/webui/resources/js/cr/ui/focus_grid.js
index ab418899878dc30c8fa661f8c94d39ed8ad7fb07..ada2d2518a7b99748e0e0a14b5984be5454f5d8b 100644
--- a/ui/webui/resources/js/cr/ui/focus_grid.js
+++ b/ui/webui/resources/js/cr/ui/focus_grid.js
@@ -139,14 +139,39 @@ cr.define('cr.ui', function() {
     },
 
     /**
-     * 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) {
+      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_;
-      this.rows.push(row);
+
+      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);
+      }
     },
 
     /**