Created attachment 322889 [details] [review]
Fix memory leak

There is a memory leak with opengl contexts.
There is 2 context being created:
this->priv->other_context =           gst_gl_context_new_wrapped (this->priv->display, gl_handle, platform, gl_api);
widget->priv->context = gst_gl_context_new (widget->priv->display);

Sink acquires them via qt_item_get_qt_context/qt_item_get_context which do gst_object_ref before returning object.

The attachment fixes the issue on my side. Context get properly deleted and associated thread quits. I am not sure though if my attachment would work in all cases - if window is hidden opengl context would be lost. But this case is already not handled by qmlglsink so I did not make any changes).