HTML：

<google-map center="map.center" zoom="map.zoom" pan="true" draggable="true" bounds="maps.bounds">

JS：

$scope.map = {
        // http://angular-google-maps.org/use
        center: {
            latitude: 34.04858,longitude: -84.29431
        },zoom: 16,lineStyle: {
            color: '#333',weight: 5,opacity: 0.7
        },bounds:{}

    };    
// in another call...............
$scope.map.bounds={
                          northeast : northeast,southwest: southwest
                        }
  $scope.$apply();