token-server: Add protos for new API for generating service account tokens.

tokenserver/client/tokenclient_test.go

 // Copyright 2016 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package client
 
 import (
         "crypto/x509"
         "testing"
         "time"
@@ skipping 75 matching lines @@
 type fakeRPCClient struct {
         In  minter.MintMachineTokenRequest
         Out minter.MintMachineTokenResponse
 }
 
 func (f *fakeRPCClient) MintMachineToken(ctx context.Context, in *minter.MintMachineTokenRequest, opts ...grpc.CallOption) (*minter.MintMachineTokenResponse, error) {
         f.In = *in
         return &f.Out, nil
 }
 
-func (f *fakeRPCClient) MintDelegationToken(context.Context, *minter.MintDelegationTokenRequest, ...grpc.CallOption) (*minter.MintDelegationTokenResponse, error) {
-        panic("not implemented")
-}
-
 // fakeSigner implements Signer.
 type fakeSigner struct{}
 
 func (f *fakeSigner) Algo(ctx context.Context) (x509.SignatureAlgorithm, error) {
         return x509.SHA256WithRSA, nil
 }
 
 func (f *fakeSigner) Certificate(ctx context.Context) ([]byte, error) {
         return []byte("fake certificate"), nil
 }
 
 func (f *fakeSigner) Sign(ctx context.Context, blob []byte) ([]byte, error) {
         return []byte("fake signature"), nil
 }