AAPT2: Fail compiling when private symbols are referenced

Also moved some XML specific stuff into its own directory,
and refactored ReferenceLinker a bit.

Change-Id: I912247a82023c1bbf72dc191fbdaf62858cbec0c
diff --git a/tools/aapt2/java/ProguardRules.h b/tools/aapt2/java/ProguardRules.h
index be61eb9..aafffd3 100644
--- a/tools/aapt2/java/ProguardRules.h
+++ b/tools/aapt2/java/ProguardRules.h
@@ -19,8 +19,7 @@
 
 #include "Resource.h"
 #include "Source.h"
-
-#include "process/IResourceTableConsumer.h"
+#include "xml/XmlDom.h"
 
 #include <map>
 #include <ostream>
@@ -47,8 +46,8 @@
     std::map<std::u16string, std::set<Source>> mKeepMethodSet;
 };
 
-bool collectProguardRulesForManifest(const Source& source, XmlResource* res, KeepSet* keepSet);
-bool collectProguardRules(const Source& source, XmlResource* res, KeepSet* keepSet);
+bool collectProguardRulesForManifest(const Source& source, xml::XmlResource* res, KeepSet* keepSet);
+bool collectProguardRules(const Source& source, xml::XmlResource* res, KeepSet* keepSet);
 
 bool writeKeepSet(std::ostream* out, const KeepSet& keepSet);