Better backend for hardware layers.

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
diff --git a/libs/hwui/Android.mk b/libs/hwui/Android.mk
index 29158e5..c49be93 100644
--- a/libs/hwui/Android.mk
+++ b/libs/hwui/Android.mk
@@ -13,6 +13,7 @@
 		FboCache.cpp \
 		GradientCache.cpp \
 		LayerCache.cpp \
+		LayerRenderer.cpp \
 		Matrix.cpp \
 		OpenGLDebugRenderer.cpp \
 		OpenGLRenderer.cpp \