Move channel_filter.h from include/ tree to src/ tree.
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index a3c4a10..3c81c48 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -762,7 +762,6 @@
INPUT = include/grpc++/alarm.h \
include/grpc++/channel.h \
-include/grpc++/channel_filter.h \
include/grpc++/client_context.h \
include/grpc++/completion_queue.h \
include/grpc++/create_channel.h \
@@ -864,6 +863,7 @@
src/cpp/common/secure_auth_context.h \
src/cpp/server/secure_server_credentials.h \
src/cpp/client/create_channel_internal.h \
+src/cpp/common/channel_filter.h \
src/cpp/server/dynamic_thread_pool.h \
src/cpp/server/thread_pool_interface.h \
src/cpp/client/secure_credentials.cc \