Comment 2 for bug 1256702

This is high risk with respect to performance.

Blending is slower than not blending. And preventing the occlusion optimizations (and bypass) from kicking in is much slower again.

If it's a temporary thing like during transitions then that's probably OK. Otherwise it should be off the table. Because we're potentially talking about throwing out all the performance work that's been done so far, if we implement this.