fix(upgrade): leak when angular1 destroys element

Fixes #6401

Closes #7935

modules/angular2/src/upgrade/downgrade_ng2_adapter.ts

@@ -160,7 +160,7 @@ export class DowngradeNg2ComponentAdapter {
   }
 
   registerCleanup() {
-    this.element.bind('$remove', () => this.viewManager.destroyRootHostView(this.hostViewRef));
+    this.element.bind('$destroy', () => this.viewManager.destroyRootHostView(this.hostViewRef));
   }
 }
 

modules/angular2/test/upgrade/upgrade_spec.ts

@@ -230,6 +230,35 @@ export function main() {
                });
 
          }));
+
+      it('should properly run cleanup when ng1 directive is destroyed',
+         inject([AsyncTestCompleter], (async) => {
+           var adapter: UpgradeAdapter = new UpgradeAdapter();
+           var ng1Module = angular.module('ng1', []);
+           var onDestroyed: EventEmitter<string> = new EventEmitter<string>();
+
+           ng1Module.directive('ng1', () => {
+             return {
+               template: '<div ng-if="!destroyIt"><ng2></ng2></div>',
+               controller: function($rootScope, $timeout) {
+                 $timeout(function() { $rootScope.destroyIt = true; });
+               }
+             };
+           });
+
+           var Ng2 = Component({selector: 'ng2', template: 'test'})
+                         .Class({
+                           constructor: function() {},
+                           ngOnDestroy: function() { onDestroyed.emit('destroyed'); }
+                         });
+           ng1Module.directive('ng2', adapter.downgradeNg2Component(Ng2));
+           var element = html('<ng1></ng1>');
+           adapter.bootstrap(element, ['ng1'])
+               .ready((ref) => {onDestroyed.subscribe(() => {
+                        ref.dispose();
+                        async.done();
+                      })});
+         }));
     });
 
     describe('upgrade ng1 component', () => {