print preview: Fix visual tab order for "Print"/"Cancel" buttons.

ui/webui/resources/js/cr/ui/node_utils.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.exportPath('cr.ui');
+
+/**
+ * Reverse the child elements of any found button strips if they haven't already
+ * been reversed. This is necessary because WebKit does not alter the tab order
+ * for elements that are visually reversed using flex-direction: reverse, and
+ * the button order is reversed for views. See http://webk.it/62664 for more
+ * information.
+ * @param {Node=} opt_root Starting point for button strips to reverse.
+ */
+cr.ui.reverseButtonStrips = function(opt_root) {
+  if (!(cr.isWindows || cr.isChromeOS)) {
+    // Only reverse on platforms that need it (differ from the HTML order).
+    return;
+  }
+
+  var root = opt_root || document;
+  var buttonStrips = root.querySelectorAll('.button-strip:not([reversed])');
+  for (var j = 0; j < buttonStrips.length; j++) {
+    var buttonStrip = buttonStrips[j];
+
+    var childNodes = buttonStrip.childNodes;
+    for (var i = childNodes.length - 1; i >= 0; i--) {
+      buttonStrip.appendChild(childNodes[i]);
+    }
+
+    buttonStrip.setAttribute('reversed', '');
+  }
+};