Fix some ChromeVox Closure compiler errors.

chrome/browser/resources/chromeos/chromevox/walkers/layout_line_walker.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.
 
 /**
  * @fileoverview A JavaScript class for walking lines consisting of one or more
  * clickable nodes.
  */
 
 
@@ skipping 154 matching lines @@
     rRect = rSel.start.node.getBoundingClientRect();
   }
   return lRect.bottom != rRect.bottom;
 };
 
 
 /**
  * Determines if node should force a line break.
  * This is used for elements with unusual semantics, such as multi-line
  * text fields, where the behaviour would otherwise be confusing.
- * @param {!Node} node Node.
+ * @param {Node} node Node.
  * @return {boolean} True if the node should appear next to a line break.
  * @private
  */
 cvox.LayoutLineWalker.prototype.wantsOwnLine_ = function(node) {
+  if (!node) {
+    return false;
+  }
   return node instanceof HTMLTextAreaElement ||
       node.parentNode instanceof HTMLTextAreaElement;
 };
 
 
 /**
  * Extends a given cursor selection up to the next visual line break.
  * @param {!cvox.CursorSelection} start The selection.
  * @return {!cvox.CursorSelection} The resulting selection.
  * @private
@@ skipping 46 matching lines @@
   if (sel && cur.absEquals(sel)) {
     if (valueSelectionSpan) {
       braille.startIndex = nodeStart + item.getSpanStart(valueSelectionSpan);
       braille.endIndex = nodeStart + item.getSpanEnd(valueSelectionSpan);
     } else {
       braille.startIndex = nodeStart;
       braille.endIndex = nodeStart + 1;
     }
   }
 };