Switch several enums to enum classes

Change-Id: I00ecd0b61657196b51704f70ca31a9d1c1ac254e
diff --git a/libs/hwui/Layer.cpp b/libs/hwui/Layer.cpp
index 928f91b..e748221 100644
--- a/libs/hwui/Layer.cpp
+++ b/libs/hwui/Layer.cpp
@@ -36,7 +36,7 @@
 namespace uirenderer {
 
 Layer::Layer(Type layerType, RenderState& renderState, uint32_t layerWidth, uint32_t layerHeight)
-        : state(kState_Uncached)
+        : state(State::Uncached)
         , caches(Caches::getInstance())
         , renderState(renderState)
         , texture(caches)