First pass at flagged resources

This gets the main parts of resource flagging in place and the basic use
case of flagging with an xml attribute working.

Test: Automated
Bug: 329436914
Flag: EXEMPT Aconfig not supported on host tools
Change-Id: Id2b5ba450d05da00a922e98ca204b6e5aa6c6c24
diff --git a/tools/aapt2/Resource.h b/tools/aapt2/Resource.h
index 7ba3277..a274f04 100644
--- a/tools/aapt2/Resource.h
+++ b/tools/aapt2/Resource.h
@@ -69,6 +69,8 @@
   kXml,
 };
 
+enum class FlagStatus { NoFlag = 0, Disabled = 1, Enabled = 2 };
+
 android::StringPiece to_string(ResourceType type);
 
 /**