Relax ShaderEffectSource's sourceItem vs window handling.

For dynamically loaded items, the window may not be set
on either the source or the item, so we need to be a bit
more relaxed in our checking.

This fixes a regression for dynamically loaded GaussianBlur.

Change-Id: I3e888405a95058ca79ecd2dff42c0ed4c8fff065
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Compare doesn't work for colors, so compare the channels explcitily.

Change-Id: I7a21328700c85b5b79dbb4342817e28833dece70
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Remove alpha channel from images that doesn't actually have alpha.

We did this for QPixmap since forever, and it has a huge impact
on rendering performance, so there is no reason why we shouldn't
spend that extra bit of time.

Change-Id: Ibd2e6d585525a5b5a975b8d7498c21dec00647c5
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Fix memory leak and crash with transform animators.

Every time initialize() was called, we would increment the ref on
an item. However, initialize is called every time the job is started,
so the ref would increase and only decrease once, leading to a leaked
helper. Change it to only increment the first time.

A different problem was that when an item was destroyed, we could run
the risk of the QQuickTransformAnimatorJob destructor being called
with the helper's item being null. This would lead to the helper not
being removed from the cache and a dangling helper would remain in the
transforms cache. Now change it so that when a target is destroyed, we
explicitly destroy the helper as well (as no animation can happen then
anyway) and reset all pointers in the job.

Change-Id: I1ce76db134bbc1871d32f1224ba5b68a4a4eeafa
Reviewed-by: Michael Brasser <michael.brasser@live.com>