Google Map control error - Cannot read property 'ZoomControlStyle' of undefined ?

I'm using google map control to get the map view related to my address.



I am getting this error "Cannot read property 'ZoomControlStyle' of undefined " at below code.





The following classes are not declared even if their files have been loaded:





{

layout: 'fit',

xtype: 'map',

//map : google.maps.Map,

mapOptions: {

zoom : 16,

panControl: false,

zoomControl: true,

scaleControl: true,

streetViewControl: false,

zoomControlOptions: {

style: google.maps.ZoomControlStyle.SMALL,

position: google.maps.ControlPosition.LEFT_BOTTOM

}

},

}





what's wrong here please help me.