initial commit of tracing context files
diff --git a/build.yaml b/build.yaml
index 6eb23d6..49ba987 100644
--- a/build.yaml
+++ b/build.yaml
@@ -29,6 +29,7 @@
   - src/core/ext/census/mlog.h
   - src/core/ext/census/resource.h
   - src/core/ext/census/rpc_metric_id.h
+  - src/core/ext/census/trace_context.h
   src:
   - src/core/ext/census/base_resources.c
   - src/core/ext/census/context.c
@@ -42,6 +43,7 @@
   - src/core/ext/census/operation.c
   - src/core/ext/census/placeholders.c
   - src/core/ext/census/resource.c
+  - src/core/ext/census/trace_context.c
   - src/core/ext/census/tracing.c
   plugin: census_grpc_plugin
   uses:
@@ -1344,6 +1346,16 @@
   - grpc
   - gpr_test_util
   - gpr
+- name: census_trace_context_test
+  build: test
+  language: c
+  src:
+  - test/core/census/trace_context_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: channel_create_test
   build: test
   language: c