AAPT2: Define intermediate compiled XML proto

This proto format is meant to encapsulate more information
that is specific to Android and allows for easier validation
and manipulation across tools.

Test: make aapt2_tests
Change-Id: I13bc34a460671fc0a36246be0d287a3d37d244d6
diff --git a/tools/aapt2/unflatten/BinaryResourceParser.cpp b/tools/aapt2/unflatten/BinaryResourceParser.cpp
index 728d1f4..892aee6 100644
--- a/tools/aapt2/unflatten/BinaryResourceParser.cpp
+++ b/tools/aapt2/unflatten/BinaryResourceParser.cpp
@@ -544,7 +544,7 @@
     const ResTable_map_entry* map) {
   std::unique_ptr<Array> array = util::make_unique<Array>();
   for (const ResTable_map& map_entry : map) {
-    array->items.push_back(ParseValue(name, config, map_entry.value));
+    array->elements.push_back(ParseValue(name, config, map_entry.value));
   }
   return array;
 }