fix($browser): detect changes to the browser url that happened in sync

Closes angular#6976.

Author: tbosch

src/ng/browser.js

@@ -234,6 +234,13 @@ function Browser(window, document, $log, $sniffer) {
     return callback;
   };
 
+  /**
+   * Checks whether the url has changed outside of Angular.
+   * Needs to be exported to be able to check for changes that have been done in sync,
+   * as hashchange/popstate events fire in async.
+   */
+  self.$$checkUrlChangedOutsideAngular = fireUrlChange;
+
   //////////////////////////////////////////////////////////////
   // Misc API
   //////////////////////////////////////////////////////////////

src/ng/rootScope.js

@@ -687,6 +687,8 @@ function $RootScopeProvider(){
             logIdx, logMsg, asyncTask;
 
         beginPhase('$digest');
+        // Check for changes to browser url that happened in sync with the call to $digest
+        $browser.$$checkUrlChangedOutsideAngular();
 
         lastDirtyWatch = null;
 

src/ngMock/angular-mocks.js

@@ -56,6 +56,8 @@ angular.mock.$Browser = function() {
     return listener;
   };
 
+  self.$$checkUrlChangedOutsideAngular = angular.noop;
+
   self.cookieHash = {};
   self.lastCookieHash = {};
   self.deferredFns = [];

test/ng/locationSpec.js

@@ -769,6 +769,28 @@ describe('$location', function() {
     });
 
 
+    it('should update location when location changed outside of Angular', function() {
+      module(function($windowProvider, $locationProvider, $browserProvider) {
+        $locationProvider.html5Mode(true);
+        $browserProvider.$get = function($document, $window, $log, $sniffer) {
+          var b = new Browser($window, $document, $log, $sniffer);
+          b.pollFns = [];
+          return b;
+        };
+      });
+      inject(function($rootScope, $browser, $location, $sniffer){
+        if ($sniffer.history) {
+          window.history.replaceState(null, '', '/hello');
+          // Verify that infinite digest reported in #6976 no longer occurs
+          expect(function() {
+            $rootScope.$digest();
+          }).not.toThrow();
+          expect($location.path()).toBe('/hello');
+        }
+      });
+    });
+
+
     it('should rewrite when hashbang url given', function() {
       initService(true, '!', true);
       inject(