Button: Batched class changes to improve performance. Fixes #6934. Button: Batch class changes to improve performance.

(cherry picked from commit 5b104db)

Author: Adovenmuehle

ui/jquery.ui.button.js

@@ -290,27 +290,32 @@ $.widget( "ui.button", {
 				.appendTo( buttonElement.empty() )
 				.text(),
 			icons = this.options.icons,
-			multipleIcons = icons.primary && icons.secondary;
+			multipleIcons = icons.primary && icons.secondary,
+			buttonClasses = [];  
+
 		if ( icons.primary || icons.secondary ) {
-			buttonElement.addClass( "ui-button-text-icon" +
-				( multipleIcons ? "s" : ( icons.primary ? "-primary" : "-secondary" ) ) );
+			buttonClasses.push( "ui-button-text-icon" + ( multipleIcons ? "s" : ( icons.primary ? "-primary" : "-secondary" ) ) );
+
 			if ( icons.primary ) {
 				buttonElement.prepend( "<span class='ui-button-icon-primary ui-icon " + icons.primary + "'></span>" );
 			}
+
 			if ( icons.secondary ) {
 				buttonElement.append( "<span class='ui-button-icon-secondary ui-icon " + icons.secondary + "'></span>" );
 			}
+
 			if ( !this.options.text ) {
-				buttonElement
-					.addClass( multipleIcons ? "ui-button-icons-only" : "ui-button-icon-only" )
-					.removeClass( "ui-button-text-icons ui-button-text-icon-primary ui-button-text-icon-secondary" );
+				buttonClasses.push( multipleIcons ? "ui-button-icons-only" : "ui-button-icon-only" );
+				buttonElement.removeClass( "ui-button-text-icons ui-button-text-icon-primary ui-button-text-icon-secondary" );
+
 				if ( !this.hasTitle ) {
 					buttonElement.attr( "title", buttonText );
 				}
 			}
 		} else {
-			buttonElement.addClass( "ui-button-text-only" );
+			buttonClasses.push( "ui-button-text-only" );
 		}
+		buttonElement.addClass( buttonClasses.join( " " ) );
 	}
 });