fix(tabs): improves performance by reducing the number of digests caused by tabs

Related to #3101

Author: Robert Messerle

src/components/tabs/js/tabsController.js

@@ -31,6 +31,7 @@ function MdTabsController ($scope, $element, $window, $timeout, $mdConstant, $md
   ctrl.shouldCenterTabs = shouldCenterTabs();
 
   //-- define public methods
+  ctrl.updatePagination = $mdUtil.debounce(updatePagination, 100);
   ctrl.redirectFocus = redirectFocus;
   ctrl.attachRipple = attachRipple;
   ctrl.shouldStretchTabs = shouldStretchTabs;
@@ -79,7 +80,7 @@ function MdTabsController ($scope, $element, $window, $timeout, $mdConstant, $md
   function bindEvents () {
     angular.element($window).on('resize', handleWindowResize);
     angular.element(elements.paging).on('DOMSubtreeModified', ctrl.updateInkBarStyles);
-    angular.element(elements.paging).on('DOMSubtreeModified', updatePagination);
+    angular.element(elements.paging).on('DOMSubtreeModified', ctrl.updatePagination);
   }
 
   function configureWatchers () {
@@ -569,11 +570,9 @@ function MdTabsController ($scope, $element, $window, $timeout, $mdConstant, $md
         oldIndex = ctrl.lastSelectedIndex,
         ink = angular.element(elements.inkBar);
     if (!angular.isNumber(oldIndex)) return;
-    if (newIndex < oldIndex) {
-      ink.addClass('md-left').removeClass('md-right');
-    } else if (newIndex > oldIndex) {
-      ink.addClass('md-right').removeClass('md-left');
-    }
+    ink
+        .toggleClass('md-left', newIndex < oldIndex)
+        .toggleClass('md-right', newIndex > oldIndex);
   }
 
   /**