添加场景缩放类别

src/core/widget/ZoomController.js

 import Widget from './Widget'
 import { DomUtil } from '../utils'
 import Icon from '../icon'
+import State from '@/core/state/State'
 
 const { Cesium } = DC.Namespace
 
     this._zoomInEl = undefined
     this._zoomOutEl = undefined
     this._refreshEl = undefined
+    this.type = Widget.getWidgetType('zoom_controller')
+    this._state = State.INITIALIZED
   }
 
   /**
   }
 }
 
+Widget.registerType('zoom_controller')
+
 export default ZoomController