This change removes the need for the SortedList and instead just
add a generated id to each FBO stored in the cache. This is an
artificial way to store several FBOs with the same dimensions.
Change-Id: I9638364e9bdc0f2391261937a0c86096f20505bf
The cache is used to draw layers so that a new
texture does not have to be recreated every time
a call to saveLayer() happens.
The FBO cache used a KeyedVector, which is a bad
idea. The cache should be able to store several
FBOs of the same size (this happens a lot during
scrolling with fading edges for instance.) This
will be changed in a future CL.
Change-Id: Ic316189e625f0dbcf0d273a71cc981a433d48726