tst_mediaobject exits with 0,1 Kill

The auto test completes but exits as a crash.

Gareth writes:
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Well, the obvious candidate is
0c8d49ca: Added support for video surfaces to Phonon MMF backend

This refactored the backend pretty heavily, introduced some new ABCs etc.

I'd suggest that you first try reverting this and see if it fixes the crash.

One possible cause is that some objects both:

• are owned as a QScopedPointer
• inherit from QObject and have a non-NULL parent pointer
  See e.g. Backend::m_effectFactory.

So maybe we're seeing a double deletion when objects are deallocated? (But (a) this is unlikely because ~QObject removes itself from the parent's children array and (b) we never saw it before)

Anyway, identifying the commit which causes this would be a good first step.