Revert "Revert "Proto API for LB request/responses""
diff --git a/package.json b/package.json
index 1b79ecf..b8f8c0a 100644
--- a/package.json
+++ b/package.json
@@ -128,6 +128,7 @@
     "src/core/client_config/client_config.h",
     "src/core/client_config/connector.h",
     "src/core/client_config/initial_connect_string.h",
+    "src/core/client_config/lb_policies/load_balancer_api.h",
     "src/core/client_config/lb_policies/pick_first.h",
     "src/core/client_config/lb_policies/round_robin.h",
     "src/core/client_config/lb_policy.h",
@@ -188,6 +189,7 @@
     "src/core/json/json_common.h",
     "src/core/json/json_reader.h",
     "src/core/json/json_writer.h",
+    "src/core/proto/grpc/lb/v0/load_balancer.pb.h",
     "src/core/statistics/census_interface.h",
     "src/core/statistics/census_rpc_stats.h",
     "src/core/surface/api_trace.h",
@@ -229,6 +231,10 @@
     "src/core/transport/transport_impl.h",
     "src/core/census/aggregation.h",
     "src/core/census/rpc_metric_id.h",
+    "third_party/nanopb/pb.h",
+    "third_party/nanopb/pb_common.h",
+    "third_party/nanopb/pb_decode.h",
+    "third_party/nanopb/pb_encode.h",
     "src/core/httpcli/httpcli_security_connector.c",
     "src/core/security/base64.c",
     "src/core/security/client_auth_filter.c",
@@ -265,6 +271,7 @@
     "src/core/client_config/connector.c",
     "src/core/client_config/default_initial_connect_string.c",
     "src/core/client_config/initial_connect_string.c",
+    "src/core/client_config/lb_policies/load_balancer_api.c",
     "src/core/client_config/lb_policies/pick_first.c",
     "src/core/client_config/lb_policies/round_robin.c",
     "src/core/client_config/lb_policy.c",
@@ -328,6 +335,7 @@
     "src/core/json/json_reader.c",
     "src/core/json/json_string.c",
     "src/core/json/json_writer.c",
+    "src/core/proto/grpc/lb/v0/load_balancer.pb.c",
     "src/core/surface/alarm.c",
     "src/core/surface/api_trace.c",
     "src/core/surface/byte_buffer.c",
@@ -382,6 +390,9 @@
     "src/core/census/operation.c",
     "src/core/census/placeholders.c",
     "src/core/census/tracing.c",
+    "third_party/nanopb/pb_common.c",
+    "third_party/nanopb/pb_decode.c",
+    "third_party/nanopb/pb_encode.c",
     "third_party/zlib/crc32.h",
     "third_party/zlib/deflate.h",
     "third_party/zlib/gzguts.h",