The parent of the QDbusAdaptor has to be a Device, and now it was a
KdeConnectPlugin for the Notifications plugin.
Instead of passing the parent (that is actually a Device) to the
QDbusAdaptor as we were doing in the Battery plugin, I preferred to get the
actual Device from the KdeConnectPlugin, even though it needs a const_cast.
Ported using KDELibs4Support, for a smaller delta, so we can keep
developing on master until we decide not to.
At the moment, it builds and installs but tests don't pass because
of a QCA2 initialization problem I didn't manage to debug yet.
CCMAIL: kdeconnect@kde.org
