Adding C++ metadata processor.

- Had to chnage the core API to add a destroy function pointer in
  grpc_auth_metadata_processor.
- Tested end to end.
- Fixed some issues in the server_auth_filter (we were not checking the
  length which put us at risk of an overflow).

1 files changed, 1 insertions, 0 deletions

diff --git a/include/grpc/grpc_security.h b/include/grpc/grpc_security.h
index e2205eea30..0b540c0e66 100644
--- a/include/grpc/grpc_security.h
+++ b/include/grpc/grpc_security.h
@@ -293,6 +293,7 @@ typedef struct {
   void (*process)(void *state, grpc_auth_context *context,
                   const grpc_metadata *md, size_t num_md,
                   grpc_process_auth_metadata_done_cb cb, void *user_data);
+  void (*destroy)(void *state);
   void *state;
 } grpc_auth_metadata_processor;