moved core_codegen from src/cpp/... to include/grpc++/...
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index ce1d6ac..bdc4534 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -770,6 +770,7 @@
include/grpc++/grpc++.h \
include/grpc++/impl/call.h \
include/grpc++/impl/client_unary_call.h \
+include/grpc++/impl/codegen/core_codegen.h \
include/grpc++/impl/grpc_library.h \
include/grpc++/impl/method_handler_impl.h \
include/grpc++/impl/proto_utils.h \
@@ -859,8 +860,8 @@
include/grpc++/impl/codegen/config_protobuf.h \
include/grpc++/support/config.h \
include/grpc++/support/config_protobuf.h \
+include/grpc++/impl/codegen/core_codegen.h \
src/cpp/client/secure_credentials.h \
-src/cpp/common/core_codegen.h \
src/cpp/common/secure_auth_context.h \
src/cpp/server/secure_server_credentials.h \
src/cpp/client/create_channel_internal.h \