Simplify the weeks-per-year calculation `WP_Date_Query::validate_date_values()`.

Props luciole135.
Fixes #30845.
Built from https://develop.svn.wordpress.org/trunk@33803


git-svn-id: http://core.svn.wordpress.org/trunk@33771 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/date.php

@@ -355,10 +355,11 @@ class WP_Date_Query {
 
 		// Weeks per year.
 		if ( isset( $_year ) ) {
-			// If we have a specific year, use it to calculate number of weeks.
-			$date = new DateTime();
-			$date->setISODate( $_year, 53 );
-			$week_count = $date->format( "W" ) === "53" ? 53 : 52;
+			/*
+			 * If we have a specific year, use it to calculate number of weeks.
+			 * Note: the number of weeks in a year is the date in which Dec 28 appears.
+			 */
+			$week_count = date( 'W', mktime( 0, 0, 0, 12, 28, $_year ) );
 
 		} else {
 			// Otherwise set the week-count to a maximum of 53.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-alpha-33802';
+$wp_version = '4.4-alpha-33803';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.