Reuse the layers list
Reuse the layers list

Instead of getting the layers list twice from the Material, we
can reuse the list when we need to retrieve the first layer.

djdeath/cogl-android,gcampax/cogl,collects/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl,Distrotech/cogl,collects/cogl,spatulasnout/cogl,djdeath/cogl,djdeath/cogl-android,Distrotech/cogl,gcampax/cogl,djdeath/cogl-android,spatulasnout/cogl