The new implementation relies on OpenGLRenderer's existing layer
code instead of duplicating it. The new code is much cleaner, with
simpler and better APIs and allows tracking of drawn regions inside
layers. Region tracking is not yet enabled but this will be done
in a future CL.
Change-Id: Ie826121a2227de8252c77b992a61218defea5143
With this new backend, a hardware layer is only recreated when
its associated view is udpated. This offers fast composition
in GL and fast update of the layer in GL as well.
Change-Id: I97c43a612f5955c6bf1c192c8ca4af10fdf1d076
