Index: wp-includes/class-wp-theme.php
===================================================================
--- wp-includes/class-wp-theme.php	(revision 23185)
+++ wp-includes/class-wp-theme.php	(working copy)
@@ -922,7 +922,7 @@
 	public function get_page_templates() {
 		// If you screw up your current theme and we invalidate your parent, most things still work. Let it slide.
 		if ( $this->errors() && $this->errors()->get_error_codes() !== array( 'theme_parent_invalid' ) )
-			return array();
+			return apply_filters( 'page_templates', array() );
 
 		$page_templates = $this->cache_get( 'page_templates' );
 
@@ -949,7 +949,7 @@
 		if ( $this->parent() )
 			$page_templates += $this->parent()->get_page_templates();
 
-		return $page_templates;
+		return apply_filters( 'page_templates', $page_templates );
 	}
 
 	/**