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
This change detects empty quads in 9patches and removes them from
the mesh to avoid unnecessary blending.
Change-Id: I4500566fb4cb6845d64dcb59b522c0be7a0ec704
