Merge pull request #15883 from hcaseyal/remove_server_auth_allocation

Remove allocation in server_auth_filter

src/core/lib/security/transport/server_auth_filter.cc

@@ -44,7 +44,6 @@ struct call_data {
   grpc_metadata_array md;
   const grpc_metadata* consumed_md;
   size_t num_consumed_md;
-  grpc_auth_context* auth_context;
   grpc_closure cancel_closure;
   gpr_atm state;  // async_state
 };
@@ -178,7 +177,7 @@ static void recv_initial_metadata_ready(void* arg, grpc_error* error) {
       calld->md = metadata_batch_to_md_array(
           batch->payload->recv_initial_metadata.recv_initial_metadata);
       chand->creds->processor.process(
-          chand->creds->processor.state, calld->auth_context,
+          chand->creds->processor.state, chand->auth_context,
           calld->md.metadata, calld->md.count, on_md_processing_done, elem);
       return;
     }
@@ -215,8 +214,8 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
   // data and save it in the call context.
   grpc_server_security_context* server_ctx =
       grpc_server_security_context_create(args->arena);
-  server_ctx->auth_context = grpc_auth_context_create(chand->auth_context);
-  calld->auth_context = server_ctx->auth_context;
+  server_ctx->auth_context =
+      GRPC_AUTH_CONTEXT_REF(chand->auth_context, "server_auth_filter");
   if (args->context[GRPC_CONTEXT_SECURITY].value != nullptr) {
     args->context[GRPC_CONTEXT_SECURITY].destroy(
         args->context[GRPC_CONTEXT_SECURITY].value);