Enable testing for whether a calendar registered its primary name

In registerAlias(), return true if this instance is already registered
with the given name.

Previously there was no way for a QCalendarBackend to tell whether its
primary name registration had succeeded, during instantiation (other
than by devious hackery using a QCalendar instance with the name and
some form of back-channel in the instance).

Use this in backendFromEnum() to catch cases in which (e.g. due to a
race condition) a new instance isn't the one that got registered.

Pick-to: 6.0 5.15
Change-Id: I468ac364a68bf3574cd7f8b8b1e672d8fd969111
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

0 files changed, 0 insertions, 0 deletions