Leif Åstrand
715d9ed846
Fail during compile if required methods are missing (#18924)
A ComponentConnector must override either getWidget or createWidget for
the framework to know the type of the component's widget. Similarly
either getRenderer och createRenderer must be overridden for
AbstractRendererConnector.
Prior to this patch, the compilation succeeded when critical methods
were missing - the user just got various hard-to-debug issues when the
broken connector was used.
Change-Id: I6ec07e2f1c1b15047802e64208485b1d999c0aee