Helper code for promises to deal with status types generically (#26911)

BUILD

@@ -841,6 +841,19 @@ grpc_cc_library(
     ],
 )
 
+grpc_cc_library(
+    name = "promise_status",
+    external_deps = [
+        "absl/status",
+        "absl/status:statusor",
+    ],
+    language = "c++",
+    public_hdrs = [
+        "src/core/lib/promise/detail/status.h",
+    ],
+    deps = ["gpr_platform"],
+)
+
 grpc_cc_library(
     name = "ref_counted",
     language = "c++",

src/core/lib/promise/detail/status.h

@@ -0,0 +1,42 @@
+// Copyright 2021 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef GRPC_CORE_LIB_PROMISE_DETAIL_STATUS_H
+#define GRPC_CORE_LIB_PROMISE_DETAIL_STATUS_H
+
+#include <grpc/impl/codegen/port_platform.h>
+
+#include "absl/status/status.h"
+#include "absl/status/statusor.h"
+
+// Helpers for dealing with absl::Status/StatusOr generically
+
+namespace grpc_core {
+namespace promise_detail {
+
+// Convert with a move the input status to an absl::Status.
+template <typename T>
+absl::Status IntoStatus(absl::StatusOr<T>* status) {
+  return std::move(status->status());
+}
+
+// Convert with a move the input status to an absl::Status.
+inline absl::Status IntoStatus(absl::Status* status) {
+  return std::move(*status);
+}
+
+}  // namespace promise_detail
+}  // namespace grpc_core
+
+#endif  // GRPC_CORE_LIB_PROMISE_DETAIL_STATUS_H