mFixedSize was never set, this bug was introduced during some "cleanup", in
practice this could cause some issues when a fixed-size buffer was used and
the window was resized.
Layer::drawForSreenShot() had a typo that had no effect.
mFixedSize was used to determine if filtering was needed, which was a bit too
conservative and created a dependency between filtering and "fixed size" states
which should exist.
Now we enable filtering based on the size of the buffer vs. the size of the layer.
Change-Id: I32044e91b0c944c1b137efdceb3f01dfaa78119d
733189d408