Merge lp://qastaging/~cimi/overlay-scrollbar/fix-754927 into lp://qastaging/overlay-scrollbar

The changes are ok here, but I think there's more to the bug.

1. the user_data may contain a dead pointer, so even getting access to ->priv may fail
2. in order to avoid dead pointers still reaching the callback, shouldn't you disconnect the animation signal as well on dispose?

1. when user_data is NULL then the animation should be already stopped, in fact in (...)
2. (...) dispose I am running at first g_object_unref (priv->animation), and os-animation on dispose signal is taking care or stopping the animation itself.

A quick opinion of loic could be enough, though I think this should be fine

I merged by mistake (I backported that in a branch I was testing, and I pushed that branch with the changes inside).
I could continue developing, though

1) The design ensures the pager is alive all along the animation lifetime.

2) The pager destroys the animation object when it's disposed and I confirm the animation object takes care of removing the source from the mainloop when it's disposed.

 review approve