Introduce pragma no cover to asbtract classes

Since the unimplemented methods for abstract classes are not meant to be
actually used, they shouldn't be included in the code coverage
calculation. Thus, to address this I introduced the pragma "no cover" to
these classes.

Change-Id: Id239a2eb42d8288764b8f374d5d13ebd37af5a7d
Merge "Introduce pragma no cover to asbtract classes"