Initial boilerplate for an updatable graphics jar

Bug: 149773383
Test: builds
Test: hacks to verify that @hide apis are actually two-way hidden
Change-Id: I148b54fe47560b2335e9d878ed93bf167d6c7517
diff --git a/libs/hwui/api/system-removed.txt b/libs/hwui/api/system-removed.txt
new file mode 100644
index 0000000..d802177
--- /dev/null
+++ b/libs/hwui/api/system-removed.txt
@@ -0,0 +1 @@
+// Signature format: 2.0