base: GstBaseSrc/GstBaseSink::get_caps: add (nullable) to `filter`
The virtual method named get_caps
in both GstBaseSrc
and
GstBaseSink
has a filter
parameter which can be NULL
(the
default implementation in GstBaseSrc already considers the case).
Before this commit, there was no gtk-doc annotation representing this
fact, which caused the corresponding entry in the GIR file to also
miss this fact.
This caused bugs in other places, such inducing the Vala compiler to
wrongly introduce an assert on (filter != NULL)
in every
implementation of the get_caps
method implemented in Vala.
Edited by sebastiano-barrera