Add support for arcs.

Change-Id: I96c057ff4eb1b464b03f132da0b85333777bee4f
diff --git a/libs/hwui/Caches.h b/libs/hwui/Caches.h
index 3bac422..0a9335f 100644
--- a/libs/hwui/Caches.h
+++ b/libs/hwui/Caches.h
@@ -164,6 +164,7 @@
     CircleShapeCache circleShapeCache;
     OvalShapeCache ovalShapeCache;
     RectShapeCache rectShapeCache;
+    ArcShapeCache arcShapeCache;
     PatchCache patchCache;
     TextDropShadowCache dropShadowCache;
     FboCache fboCache;