Document more function/class/method params

To help fill out the docs start adding on docstrings
that document what a parameter is and what its meaning
and usage is to help users better understand the parameter.

Part of ongoing bug 1374202

Change-Id: I9f9a83cfb763a0a05d22efca4e0f80627ba8ca8f
Merge "Document more function/class/method params"