AAPT2: Fix overlay support

Supports the <add-resource> tag and mimics old AAPT behavior of
not allowing new resources defined unless <add-resource> was used
or --auto-add-overlay was specified.

Change-Id: I9b461137357617ade37fd7045b418b8e6450b9c4
diff --git a/tools/aapt2/ResourceUtils.h b/tools/aapt2/ResourceUtils.h
index f93a4c7..64ca971 100644
--- a/tools/aapt2/ResourceUtils.h
+++ b/tools/aapt2/ResourceUtils.h
@@ -17,6 +17,7 @@
 #ifndef AAPT_RESOURCEUTILS_H
 #define AAPT_RESOURCEUTILS_H
 
+#include "NameMangler.h"
 #include "Resource.h"
 #include "ResourceValues.h"
 #include "util/StringPiece.h"
@@ -154,6 +155,16 @@
 
 uint32_t androidTypeToAttributeTypeMask(uint16_t type);
 
+/**
+ * Returns a string path suitable for use within an APK. The path will look like:
+ *
+ * res/type[-config]/<name>.<ext>
+ *
+ * Then name may be mangled if a NameMangler is supplied (can be nullptr) and the package
+ * requires mangling.
+ */
+std::string buildResourceFileName(const ResourceFile& resFile, const NameMangler* mangler);
+
 } // namespace ResourceUtils
 } // namespace aapt