AAPT2: Enable building proto artifacts

- This will allow the bundle tool to ingest the outputs of the aapt2 link
  phase.

Bug: 64143208
Test: manual
Change-Id: I1a4b3ce5c2ffbbdc4bc642c3371a9ef2e7e9ad71
diff --git a/tools/aapt2/Debug.h b/tools/aapt2/Debug.h
index e2456c7..296d04b 100644
--- a/tools/aapt2/Debug.h
+++ b/tools/aapt2/Debug.h
@@ -31,13 +31,11 @@
 };
 
 struct Debug {
-  static void PrintTable(ResourceTable* table,
-                         const DebugPrintTableOptions& options = {});
+  static void PrintTable(const ResourceTable& table, const DebugPrintTableOptions& options = {});
   static void PrintStyleGraph(ResourceTable* table,
                               const ResourceName& target_style);
   static void DumpHex(const void* data, size_t len);
-  static void DumpXml(xml::XmlResource* doc);
-  static std::string ToString(xml::XmlResource* doc);
+  static void DumpXml(const xml::XmlResource& doc);
 };
 
 }  // namespace aapt