I had to navigate up a long class hierachy just to find out that 'mc' means message class. Improve the readability by giving the constructor arguments better names. Names in the email classes are generally bad. This change isn't fixing everything, but it's a start. Signed-off-by: Edwin Kempin <ekempin@google.com> Change-Id: I05271a09687959ef40b3c1bc942ddb21044aa999