fix for tests in angular repo (#1179)

Author: JiaLiPassion

lib/browser/register-element.ts

@@ -26,7 +26,7 @@ function patchCallbacks(target: any, targetName: string, method: string, callbac
 if(descriptor&&descriptor.value){
 descriptor.value=wrapWithCurrentZone(descriptor.value,source);
 _redefineProperty(opts.prototype,callback,descriptor);
-}else{
+}elseif(prototype[callback]){
 prototype[callback]=wrapWithCurrentZone(prototype[callback],source);
 }
 }elseif(prototype[callback]){