Setup owners for featureflag files

Change-Id: Ia7621b53907fcd42724dc5e1a7d36920fd4836dc
diff --git a/OWNERS b/OWNERS
index 6c1273f..538ca33 100644
--- a/OWNERS
+++ b/OWNERS
@@ -10,3 +10,6 @@
 sunnygoyal@google.com
 twickham@google.com
 winsonc@google.com
+
+per-file FeatureFlags.java = sunnygoyal@google.com, adamcohen@google.com
+per-file BaseFlags.java = sunnygoyal@google.com, adamcohen@google.com