Go To Implementation not recoginsing classes in Wordpress integration.

When using Go to Implementation or Go to Definition in Wordpress `functions.php` file, the following code example works as expected:

```

add_action('after_setup_theme', 'foo');

function foo()
{

}

```

That is, clicking Go to Implementation on 'foo' as the second `add_action()` argument properly goes to the function definition.

However, the following does not work as expected:

```

class Abc {

    public static function init() {

        add_action('after_setup_theme', array(__CLASS__, 'foo'));

    }

     public static function foo() {

    }

}

Abc::init();

```

That is, clicking Go to Implementation on 'foo' as the second `add_action()` argument properly _does not_ go to the function definition.