Slider: Set/unset class "ui-state-disabled" in sync with disabled option

Fixes gh-6857

js/widgets/forms/slider.js

@@ -581,7 +581,9 @@ $.widget( "mobile.slider", $.extend( {
 	_setDisabled: function( value ) {
 		value = !!value;
 		this.element.prop( "disabled", value );
-		this.slider.toggleClass( "ui-state-disabled" ).attr( "aria-disabled", value );
+		this.slider
+			.toggleClass( "ui-state-disabled", value )
+			.attr( "aria-disabled", value );
 	}
 
 }, $.mobile.behaviors.formReset ) );

tests/unit/slider/index.html

@@ -117,6 +117,11 @@ <h2 id="qunit-userAgent"></h2>
         <label for="remove-events-slider">Input slider:</label>
         <input type="range" name="remove-events-slider" id="remove-events-slider" value="25" min="0" max="100"/>
     </div>
+
+	<label>Input slider:
+		<input type="range" name="disable-test" id="disable-test" value="17" min="0" max="100"/>
+	</label>
+
 </div>
 
 <div id="enhancetest">

tests/unit/slider/slider_core.js

@@ -66,7 +66,28 @@
 	test( "slider input is not wrapped in div.ui-input-text", function() {
 		ok( ! $( "#textinput-test" ).parents().is( "div.ui-input-text" ), "slider input is not wrapped in div.ui-input-text" );
 	});
-
+
+	test( "slider is enabled/disabled correctly", function() {
+		var slider = $( "#disable-test" ),
+			track = slider.siblings( "div" );
+
+			testDisabled = function( prefix, expectedDisabled ) {
+				deepEqual( !!track.attr( "aria-disabled" ), expectedDisabled,
+					prefix + "'aria-disabled' is " + expectedDisabled );
+				deepEqual( !!slider.attr( "disabled" ), expectedDisabled,
+					prefix + "'disabled' property is " + expectedDisabled );
+				deepEqual( track.hasClass( "ui-state-disabled" ), expectedDisabled,
+					prefix + "track class 'ui-state-disabled' is " +
+						( expectedDisabled ? "on" : "off" ) );
+			};
+
+		testDisabled( "Initially: ", false );
+		slider.slider( "option", "disabled", true );
+		testDisabled( "After setting option 'disabled' to true: ", true );
+		slider.slider( "option", "disabled", true );
+		testDisabled( "After setting option 'disabled' to true a second time: ", true );
+	});
+
 	test( "refresh is triggered on mouseup", function() {
 		expect( 1 );
 		var slider = $( "#mouseup-refresh" );