public void setGridCallback(GridCallback gridCallback) {
        this.gridCallback = gridCallback;
    }
Crop bitmap async
@param callback {@link CropperCallback}
@return State STARTED if cropping will start else FAILURE_GESTURE_IN_PROCESS
if cropping can not be started because the user is in the middle of a gesture.
nocropper/src/main/java/com/fenchtose/nocropper/CropperView.java