Fix a list management bug exposed by new locking scheme in client_channel
diff --git a/src/core/transport/chttp2/internal.h b/src/core/transport/chttp2/internal.h
index c8c46f0..7f98a5b 100644
--- a/src/core/transport/chttp2/internal.h
+++ b/src/core/transport/chttp2/internal.h
@@ -63,6 +63,7 @@
   GRPC_CHTTP2_LIST_WRITABLE_WINDOW_UPDATE,
   GRPC_CHTTP2_LIST_PARSING_SEEN,
   GRPC_CHTTP2_LIST_CLOSED_WAITING_FOR_PARSING,
+  GRPC_CHTTP2_LIST_CANCELLED_WAITING_FOR_WRITING,
   GRPC_CHTTP2_LIST_INCOMING_WINDOW_UPDATED,
   /** streams that are waiting to start because there are too many concurrent
       streams on the connection */
@@ -526,6 +527,13 @@
     grpc_chttp2_transport_global *transport_global,
     grpc_chttp2_stream_global **stream_global);
 
+void grpc_chttp2_list_add_cancelled_waiting_for_writing(
+    grpc_chttp2_transport_global *transport_global,
+    grpc_chttp2_stream_global *stream_global);
+int grpc_chttp2_list_pop_cancelled_waiting_for_writing(
+    grpc_chttp2_transport_global *transport_global,
+    grpc_chttp2_stream_global **stream_global);
+
 void grpc_chttp2_list_add_read_write_state_changed(
     grpc_chttp2_transport_global *transport_global,
     grpc_chttp2_stream_global *stream_global);