PDF Embeded api - Add Api to retrieve Page dimensions

To place an annotation programatically exactly and center is precisely the document dimensions of the current page is required. Currently there is no api to retrieve these dimensions - In the old pdf javascript world this could be done by 

var rctBBox = this.getPageBox("BBox",pageNumber);

This can be then used to determine the dimensions of the bounding box of the annotation.

However, there is no equivalent of this in the Adobe Embedded PDF javascript API.