Completely detach removed nodes.

chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
index 84a6898bc5484cb177136aa76a061a54627753ab..35ebe6d51e6f4d4b780e740c7467e6789561f31a 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
@@ -284,6 +284,14 @@ cursors.Cursor.prototype = {
     newNode = newNode || this.node_;
     newIndex = goog.isDef(newIndex) ? newIndex : this.index_;
     return new cursors.Cursor(newNode, newIndex);
+  },
+
+  /**
+   * Returns whether this cursor points to a valid position.
+   * @return {boolean}
+   */
+  isValid: function() {
+    return this.node.role !== undefined;
   }
 };
 
@@ -528,6 +536,14 @@ cursors.Range.prototype = {
   isWebRange: function() {
     return this.start.node.root.role != RoleType.desktop ||
         this.end.node.root.role != RoleType.desktop;
+  },
+
+  /**
+   * Returns whether this range has valid start and end cursors.
+   * @return {boolean}
+   */
+  isValid: function() {
+    return this.start.isValid() && this.end.isValid();
   }
 };