Add flag support to styles elements

Test: Automated
Bug: 329436914
Flag: EXEMPT Aconfig not supported on host tools
Change-Id: I3041ebbaf98a90527809b541df8885edfc70d035
diff --git a/tools/aapt2/Resources.proto b/tools/aapt2/Resources.proto
index a0f60b6..fe9b4a8 100644
--- a/tools/aapt2/Resources.proto
+++ b/tools/aapt2/Resources.proto
@@ -302,6 +302,11 @@
     Plural plural = 5;
     MacroBody macro = 6;
   }
+
+  // The status of the flag the value is behind if any
+  uint32 flag_status = 7;
+  bool flag_negated = 8;
+  string flag_name = 9;
 }
 
 // Message holding a boolean, so it can be optionally encoded.