In most cases, we should never expose the XxxOperationBasis
class in method signatures. Exposing XxxOperationBasis is
not clean because the XxxOperationBasis is a big container
implementing various interfaces. We should always use interfaces
instead, and if one interface is not enough then use two or three
of them as formal parameters.

This set of changes is removing all the un-necessary use of
XxxOperationBasis in the code, including unit-tests.