Media: Grid view - correct placeholder positioning during uploads.

Preventing contextually created attachments from being added to the grid collection in Attachments.validator. Remove the previous filtering introduced in [41937] which caused the placement issue.

Merge of [42739-42740] to the 4.9 branch.

Props lancewillett, Junaidkbr, designsimply, joemcgill.
Fixes #42968.
Built from https://develop.svn.wordpress.org/branches/4.9@42848


git-svn-id: http://core.svn.wordpress.org/branches/4.9@42678 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/media-models.js

@@ -642,6 +642,15 @@ var Attachments = Backbone.Collection.extend(/** @lends wp.media.model.Attachmen
 	 * @returns {Boolean}
 	 */
 	validator: function( attachment ) {
+
+		// Filter out contextually created attachments (e.g. headers, logos, etc.).
+		if (
+			! _.isUndefined( attachment.attributes.context ) &&
+			'' !== attachment.attributes.context
+		) {
+			return false;
+		}
+
 		if ( ! this.validateDestroyed && attachment.destroyed ) {
 			return false;
 		}

wp-includes/js/media-views.js

@@ -953,9 +953,6 @@ Library = wp.media.controller.State.extend(/** @lends wp.media.controller.Librar
 			}) );
 		}
 
-		this._filterContext();
-		this.get('library').on( 'add', this._filterContext, this );
-
 		this.resetDisplays();
 	},
 
@@ -1155,20 +1152,8 @@ Library = wp.media.controller.State.extend(/** @lends wp.media.controller.Librar
 		if ( view && view.get( mode ) ) {
 			setUserSetting( 'libraryContent', mode );
 		}
-	},
-
-	/**
-	 * Filter out contextually created attachments (e.g. headers, logos, etc.)
-	 *
-	 * @since 4.9.0
-	 */
-	_filterContext: function() {
-		var library = this.get('library');
-
-		library.set( library.filter( function( item ) {
-			return item.get('context') === '';
-		} ) );
 	}
+
 });
 
 // Make selectionSync available on any Media Library state.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9.5-alpha-42847';
+$wp_version = '4.9.5-alpha-42848';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.