I figured it out. The Javascript interface is a little different from the Java interface. The response is the result. This worked ...
var query = [{'type':'/people/person','id':null,'name':null}];
gapi.client.load('freebase', 'v1', function(){
var request = gapi.client.freebase.mqlread({'query': JSON.stringify(query)});
request.execute(function(response) {
console.log(response);
});
});