Media: Disable the edit image->replace button when no item selected.

On the edit media screen, ensure that the 'replace' button is disabled until a media item is selected. Fix an issue where clicking the button with no item selected threw a JavaScript error and failed to work.

Props timmydcrawford, subrataemfluence, psiico.
Fixes #40589.


Built from https://develop.svn.wordpress.org/trunk@40902


git-svn-id: http://core.svn.wordpress.org/trunk@40752 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/media-views.js

@@ -5116,6 +5116,7 @@ ImageDetails = Select.extend({
 					style:    'primary',
 					text:     l10n.replace,
 					priority: 80,
+					requires: { selection: true },
 
 					click: function() {
 						var controller = this.controller,

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-40901';
+$wp_version = '4.9-alpha-40902';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.