Handle Apply button little bit more sanely

Change-Id: I55d48de703662f139549d764bf7c1f235111d5ab

resources/js/ext.uls.displaysettings.js

@@ -537,7 +537,7 @@
 		 */
 		markDirty: function () {
 			this.dirty = true;
-			this.$parent.$window.find( 'button.uls-settings-apply' ).prop( 'disabled', false );
+			this.$parent.enableApplyButton();
 		},
 
 		/**

resources/js/ext.uls.inputsettings.js

@@ -111,7 +111,7 @@
 		 */
 		markDirty: function () {
 			this.dirty = true;
-			this.$parent.$window.find( 'button.uls-settings-apply' ).prop( 'disabled', false );
+			this.$parent.enableApplyButton();
 		},
 
 		prepareInputmethods: function ( language ) {

resources/js/ext.uls.languagesettings.js

@@ -60,6 +60,7 @@
 		this.top = this.options.top;
 		this.modules = {};
 		this.$settingsPanel = this.$window.find( '#languagesettings-settings-panel' );
+		this.$applyButton = this.$window.find( '.uls-settings-apply' );
 		this.init();
 		this.listen();
 	}
@@ -78,7 +79,7 @@
 
 			this.$window.find( '#languagesettings-close, button.uls-settings-cancel' )
 				.on( 'click', mw.hook( 'mw.uls.settings.cancel' ).fire.bind( this ) );
-			this.$window.find( 'button.uls-settings-apply' )
+			this.$applyButton
 				.on( 'click', mw.hook( 'mw.uls.settings.apply' ).fire.bind( this ) );
 			// Hide the window when clicked outside
 			$( document.documentElement ).on( 'click', this.hide.bind( this ) );
@@ -240,16 +241,14 @@
 		 *     false to unset the busy mode.
 		 */
 		setBusy: function ( busy ) {
-			var $applyButton = this.$window.find( 'button.uls-settings-apply' );
-
 			if ( busy ) {
 				this.$window.addClass( 'waiting' );
-				$applyButton
+				this.$applyButton
 					.text( $.i18n( 'ext-uls-language-settings-applying' ) )
 					.prop( 'disabled', true );
 			} else {
 				this.$window.removeClass( 'waiting' );
-				$applyButton.text( $.i18n( 'ext-uls-language-settings-apply' ) );
+				this.$applyButton.text( $.i18n( 'ext-uls-language-settings-apply' ) );
 			}
 		},
 
@@ -282,8 +281,12 @@
 			}
 		},
 
+		enableApplyButton: function () {
+			this.$applyButton.prop( 'disabled', false );
+		},
+
 		disableApplyButton: function () {
-			this.$window.find( 'button.uls-settings-apply' ).prop( 'disabled', true );
+			this.$applyButton.prop( 'disabled', true );
 		}
 	};