diff --git a/webshell/public/nsIWebShell.h b/webshell/public/nsIWebShell.h
index ce3d7b5dda6..610cc1070cf 100644
--- a/webshell/public/nsIWebShell.h
+++ b/webshell/public/nsIWebShell.h
@@ -262,6 +262,11 @@ public:
    */
   NS_IMETHOD AddChild(nsIWebShell* aChild) = 0;
 
+  /**
+   * Remove a child WebShell.
+   */
+  NS_IMETHOD RemoveChild(nsIWebShell* aChild) = 0;
+
   /**
    * Return the child WebShell at the requested index.
    */