I think you did it wrong. Its javascript code, you should add it to your footer.php file, not functions.php.
So you want to redirect non-existing page on your WP? To google.com?
I have the same problem. Currently I’m using this hack:
// wordpress 3.8 rtl icon hack
add_action( 'admin_head', function() {
?>
<style>
span.mce_rtl:before {
content: '\f320';
}
span.mce_rtl {
-moz-transform: scaleX(-1);
-o-transform: scaleX(-1);
-webkit-transform: scaleX(-1);
transform: scaleX(-1);
filter: FlipH;
-ms-filter: "FlipH";
}
</style>
<?php
});
The flipping CSS code is from here: http://css-tricks.com/snippets/css/flip-an-image/
