要创建DragEvent，请使用量角器API。官方文件 指出：
The browser.get method loads a page. Protractor expects Angular to be present on a page, so it will throw an error if the page it is attempting to load does not contain the Angular library. (If you need to interact with a non-Angular page, you may access the wrapped web driver instance directly with browser.driver).
也使用以下模式：
browser
.actions()
.dragAndDrop(myEle, {x:100,y:100})
.perform();