Widgets: Revert [37425] and [37427].

The change can cause fatal errors under certain conditions, like when the subclass has a different function signature for `widget()` or doesn't even implement the method.

See #35981.
Built from https://develop.svn.wordpress.org/trunk@37648


git-svn-id: http://core.svn.wordpress.org/trunk@37614 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-widget.php

@@ -16,9 +16,8 @@
  *
  * @since 2.8.0
  * @since 4.4.0 Moved to its own file from wp-includes/widgets.php
- * @abstract
  */
-abstract class WP_Widget {
+class WP_Widget {
 
 	/**
 	 * Root ID for all widgets of this type.
@@ -97,13 +96,14 @@ abstract class WP_Widget {
 	 *
 	 * @since 2.8.0
 	 * @access public
-	 * @abstract
 	 *
 	 * @param array $args     Display arguments including 'before_title', 'after_title',
 	 *                        'before_widget', and 'after_widget'.
 	 * @param array $instance The settings for the particular instance of the widget.
 	 */
-	abstract public function widget( $args, $instance );
+	public function widget( $args, $instance ) {
+		die('function WP_Widget::widget() must be over-ridden in a sub-class.');
+	}
 
 	/**
 	 * Updates a particular instance of a widget.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37647';
+$wp_version = '4.6-alpha-37648';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.