The getService() and registerAsService() methods of interface objects
now have default parameters of "default" for the service name. HALs
will not have to use any service name unless they want to register
more than one service.
Test: builds
Bug: 33844934
Change-Id: I5640441f5cfc7846e854f7ea23abb76ab3628d52
Adds the default context hub hal implementation and service.
Test: Context Hub GTS tests still pass.
Change-Id: I7416ce9ec8efca7f98d2bb63606f030f4e8c8ead