Add estimator test
diff --git a/grpc.gemspec b/grpc.gemspec
index 8517292..1698024 100755
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -244,6 +244,7 @@
   s.files += %w( src/core/lib/surface/init.h )
   s.files += %w( src/core/lib/surface/lame_client.h )
   s.files += %w( src/core/lib/surface/server.h )
+  s.files += %w( src/core/lib/transport/bdp_estimator.h )
   s.files += %w( src/core/lib/transport/byte_stream.h )
   s.files += %w( src/core/lib/transport/connectivity_state.h )
   s.files += %w( src/core/lib/transport/mdstr_hash_table.h )
@@ -420,6 +421,7 @@
   s.files += %w( src/core/lib/surface/server.c )
   s.files += %w( src/core/lib/surface/validate_metadata.c )
   s.files += %w( src/core/lib/surface/version.c )
+  s.files += %w( src/core/lib/transport/bdp_estimator.c )
   s.files += %w( src/core/lib/transport/byte_stream.c )
   s.files += %w( src/core/lib/transport/connectivity_state.c )
   s.files += %w( src/core/lib/transport/mdstr_hash_table.c )