Fix C++ filter API and add test for it.
diff --git a/build.yaml b/build.yaml
index d7440fe..9078fee 100644
--- a/build.yaml
+++ b/build.yaml
@@ -2798,6 +2798,16 @@
   - grpc++
   - grpc
   - gpr
+- name: channel_filter_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/cpp/common/channel_filter_test.cc
+  deps:
+  - grpc++
+  - grpc
+  - gpr
 - name: cli_call_test
   gtest: true
   build: test