[errors] de-specialize Transient in favor of Tags.

common/gcloud/googleoauth/info.go

 // Copyright 2017 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 googleoauth
 
 import (
         "encoding/json"
         "net/http"
         "net/url"
 
         "github.com/luci/luci-go/common/errors"
         "github.com/luci/luci-go/common/logging"
+        "github.com/luci/luci-go/common/retry/transient"
         "google.golang.org/api/googleapi"
 
         "golang.org/x/net/context"
         "golang.org/x/net/context/ctxhttp"
 )
 
 const (
         // TokeninfoEndpoint is Google's token info endpoint.
         TokeninfoEndpoint = "https://www.googleapis.com/oauth2/v3/tokeninfo"
 )
@@ skipping 48 matching lines @@
         logging.Debugf(c, "POST %s", params.Endpoint)
         v := url.Values{}
         if params.IDToken != "" {
                 v.Add("id_token", params.IDToken)
         } else {
                 v.Add("access_token", params.AccessToken)
         }
         resp, err := ctxhttp.Get(c, params.Client, params.Endpoint+"?"+v.Encode())
         if err != nil {
                 logging.WithError(err).Errorf(c, "POST %s failed", params.Endpoint)
-                return nil, errors.WrapTransient(err)
+                return nil, transient.Tag.Apply(err)
         }
         defer googleapi.CloseBody(resp)
         if err := googleapi.CheckResponse(resp); err != nil {
                 logging.WithError(err).Errorf(c, "POST %s failed", params.Endpoint)
                 if apiErr, ok := err.(*googleapi.Error); ok && apiErr.Code < 500 {
                         return nil, ErrBadToken
                 }
-                return nil, errors.WrapTransient(err)
+                return nil, transient.Tag.Apply(err)
         }
 
         info := &TokenInfo{}
         if err := json.NewDecoder(resp.Body).Decode(info); err != nil {
                 // This should never happen. If it does, the token endpoint has gone mad,
                 // and maybe it will recover soon. So mark the error as transient.
                 logging.WithError(err).Errorf(c, "Bad token info endpoint response")
-                return nil, errors.WrapTransient(err)
+                return nil, transient.Tag.Apply(err)
         }
 
         return info, nil
 }