AAPT2: Add Inline Complex XML support

See: https://developer.android.com/guide/topics/resources/complex-xml-resources.html

Change-Id: I8274c85e25cabf90423141c228697e873167d136
diff --git a/tools/aapt2/xml/XmlUtil.cpp b/tools/aapt2/xml/XmlUtil.cpp
index 0e9d005..b570fd7 100644
--- a/tools/aapt2/xml/XmlUtil.cpp
+++ b/tools/aapt2/xml/XmlUtil.cpp
@@ -23,8 +23,8 @@
 namespace aapt {
 namespace xml {
 
-std::string buildPackageNamespace(const StringPiece& package) {
-    std::string result = kSchemaPublicPrefix;
+std::string buildPackageNamespace(const StringPiece& package, bool privateReference) {
+    std::string result = privateReference ? kSchemaPrivatePrefix : kSchemaPublicPrefix;
     result.append(package.data(), package.size());
     return result;
 }