clean up unit tests (ran under android) so there's no uninitialized value errors for the unit-tests/graphics/android tests, and make the tests run without gmock warning, unexpected call errors. (LP: #1172184). Fixes: https://bugs.launchpad.net/bugs/1172184, https://bugs.launchpad.net/bugs/1253486.
Approved by PS Jenkins bot, Alan Griffiths, Daniel van Vugt.