fix($animate): wait two until two digests are over until enabling animations

Even when no remote templates are to be downloaded, wait two digests until
enabling animations since all structural digests perform a post digest before
running animations.

Closes angular#8844

Author: matsko

src/ngAnimate/animate.js

@@ -412,33 +412,27 @@ angular.module('ngAnimate', ['ng'])
       $rootElement.data(NG_ANIMATE_STATE, rootAnimateState);
 
       // disable animations during bootstrap, but once we bootstrapped, wait again
-      // for another digest until enabling animations. Enter, leave and move require
+      // for another 2 digests until enabling animations. Enter, leave and move require
       // a follow-up digest so having a watcher here is enough to let both digests pass.
       // However, when any directive or view templates are downloaded then we need to
       // handle postpone enabling animations until they are fully completed and then...
       var watchFn = $rootScope.$watch(
         function() { return $templateRequest.totalPendingRequests; },
         function(val, oldVal) {
-          if (oldVal === 0) {
-            if (val === 0) {
-              $rootScope.$$postDigest(onApplicationReady);
-            }
-          } else if(val === 0) {
-            // ...when the template has been downloaded we digest twice again until the
-            // animations are set to enabled (since enter, leave and move require a
-            // follow-up).
+          if (val !== 0) return;
+          watchFn();
+
+          // ...when the template has been downloaded we digest twice again until the
+          // animations are set to enabled (since enter, leave and move require a
+          // follow-up). The same approach applies when there are no templates to download.
+          $rootScope.$$postDigest(function() {
             $rootScope.$$postDigest(function() {
-              $rootScope.$$postDigest(onApplicationReady);
+              rootAnimateState.running = false;
             });
-          }
+          });
         }
       );
 
-      function onApplicationReady() {
-        rootAnimateState.running = false;
-        watchFn();
-      }
-
       var globalAnimationCounter = 0;
       var classNameFilter = $animateProvider.classNameFilter();
       var isAnimatableClassName = !classNameFilter

test/ng/directive/ngClassSpec.js

@@ -434,7 +434,10 @@ describe('ngClass animations', function() {
     });
     inject(function($compile, $rootScope, $browser, $rootElement, $animate, $timeout, $document) {
 
-      // Animations are enabled right away since there are no remote HTTP template requests
+      // Animations need to digest twice in order to be enabled regardless if there are no template HTTP requests.
+      $rootScope.$digest();
+      digestQueue.shift()();
+
       $rootScope.$digest();
       digestQueue.shift()();