[FAB-12788] Protobuf Messages for Token Expectation

A chaincode needs to be able to set token expectations.
We need to define protobuf messages for the expectation
to be stored in the proposal response

Change-Id: I14594b6224f2e20f503c3838075d807f95632e60
Signed-off-by: Angelo De Caro <adc@zurich.ibm.com>

protos/token/expectations.proto

@@ -0,0 +1,40 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+syntax = "proto3";
+
+option go_package = "github.com/hyperledger/fabric/protos/token";
+option java_package = "org.hyperledger.fabric.protos.token";
+
+package protos;
+
+import "google/protobuf/timestamp.proto";
+import "token/transaction.proto";
+
+// TokenExpectation represent the belief that someone should achieve in terms of a token action
+message TokenExpectation {
+    oneof Expectation {
+        // PlainExpectation describes a plain token expectation
+        PlainExpectation plain_expectation = 1;
+    }
+}
+
+// PlainExpectation represent the plain expectation where no confidentiality is provided.
+message PlainExpectation {
+    oneof payload {
+        // ImportExpectation describes an token import expectation
+        PlainTokenExpectation import_expectation = 1;
+        // TransferExpectation describes a token transfer expectation
+        PlainTokenExpectation transfer_expectation = 2;
+    }
+}
+
+// PlainTokenExpectation represents the expecation that
+// certain outputs will be matched
+message PlainTokenExpectation {
+    // Outputs contains the expected outputs
+    repeated PlainOutput outputs = 1;
+}