Added handshaker.[ch] to build.yaml.
diff --git a/build.yaml b/build.yaml
index 071d4a8..21490d0 100644
--- a/build.yaml
+++ b/build.yaml
@@ -156,6 +156,7 @@
   - src/core/lib/channel/compress_filter.h
   - src/core/lib/channel/connected_channel.h
   - src/core/lib/channel/context.h
+  - src/core/lib/channel/handshaker.h
   - src/core/lib/channel/http_client_filter.h
   - src/core/lib/channel/http_server_filter.h
   - src/core/lib/compression/algorithm_metadata.h
@@ -234,6 +235,7 @@
   - src/core/lib/channel/channel_stack_builder.c
   - src/core/lib/channel/compress_filter.c
   - src/core/lib/channel/connected_channel.c
+  - src/core/lib/channel/handshaker.c
   - src/core/lib/channel/http_client_filter.c
   - src/core/lib/channel/http_server_filter.c
   - src/core/lib/compression/compression.c