The Chamberlain of Scotland was an steward of the royal household responsible for taking care of royal revenue, much like an ancient version of the Chancellor of the Exchequer.
During the time of the Wars of Independence, Edward I placed John de Sandale as his Chamberlain of Scotland. The office of Chamberlain was important because only the King, King's Lieutenant or Chamberlain could appoint sheriffs to control law and order in the land. In 1305, for instance, John Mentieth was confirmed as sheriff of Dumbarton Castle - the man who betrayed William Wallace to the English.
The Livingstons - although supporters of Edward I - were not mentioned in the ordinance of 1305 and it is likely to assume that they could not yield power over their neighbours (e.g. the Flemings of Garscadden) although whether John Mentieth could yield power from his Dumbarton sanctuary remains questionable. It could be argued that Mentieth, a Scottish patriot until his defection in 1303, would have been a less obvious choice of sheriff than the Livingstons - so perhaps his appointment was a measure of control by John de Sandale. Indeed, Mentieth was to defect back to the Scottish cause under Bruce in 1309.
Robert the Bruce, crowned in 1306, thus appointed his own Chamberlain, Stephen Dunnideer, the bishop-elect of Glasgow. Dunideer died however in 1317 before becoming bishop. He then appointed Sir Alexander Fraser of Touch Fraser as Lord Chamberlain. He died in battle in Dupplin in 12th August 1332.
It would have been a measure of Robert the Bruce's power and forgiveness, and probably of the Livingston's growing allegiance to the crown and influence, that the Chamberlain would have accepted the token of the flour in 1328, thus making Drumry a barony in its own right.