Refactor policy parsing

This change removes the ability for an overlayable resource to be
defined in multiple policy blocks within the same overlayable. This
change also changes aapt2 to use a bit mask to keep track of the parsed
policies.

Bug: 110869880
Bug: 120298168
Test: aapt2_tests
Change-Id: Ie26cd913f94a16c0b312f222bccfa48f62feceaa
diff --git a/tools/aapt2/test/Builders.h b/tools/aapt2/test/Builders.h
index d68c24d..a120484 100644
--- a/tools/aapt2/test/Builders.h
+++ b/tools/aapt2/test/Builders.h
@@ -73,8 +73,8 @@
                                  const ResourceId& id, std::unique_ptr<Value> value);
   ResourceTableBuilder& SetSymbolState(const android::StringPiece& name, const ResourceId& id,
                                        Visibility::Level level, bool allow_new = false);
-  ResourceTableBuilder& AddOverlayable(const android::StringPiece& name,
-                                       Maybe<Overlayable::Policy> policy);
+  ResourceTableBuilder& SetOverlayable(const android::StringPiece& name,
+                                       const Overlayable& overlayable);
 
   StringPool* string_pool();
   std::unique_ptr<ResourceTable> Build();