Guillaume Desmottes authored Oct 24, 2017 and Olivier Crête committed Nov 28, 2017

As stated in the existing comment, when flusing we should wait for OMX
to send the flush command complete event AND all ports being released.
We were stopping as soon as one of those condition was met.

Fix a race between FillThisBufferDone/EmptyBufferDone and the flush
EventCmdComplete messages. The OMX implementation is supposed to release
its buffers before posting the EventCmdComplete event but the ordering
isn't guaranteed as the FillThisBufferDone/EmptyBufferDone and
EventHandler callbacks can be called from different threads (cf 2.7
'Thread Safety' in the spec).

https://bugzilla.gnome.org/show_bug.cgi?id=789475