A mixin which adds the CesiumInspector widget to the Viewer widget.
Rather than being called directly, this function is normally passed as
a parameter to 
    
    
    
    
    
        
Viewer#extend, as shown in the example below.
    | Name | Type | Description | 
|---|---|---|
| viewer | Viewer | The viewer instance. | 
Throws:
- 
    DeveloperError : viewer is required.
Example:
var viewer = new Cesium.Viewer('cesiumContainer');
viewer.extend(Cesium.viewerCesiumInspectorMixin);