Interface update, per-method Contexts.

filter/featureBreaker/mail.go

 // Copyright 2015 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 featureBreaker
 
 import (
         "github.com/luci/gae/service/mail"
         "golang.org/x/net/context"
 )
 
 type mailState struct {
         *state
 
-        mail.Interface
+        mail.RawInterface
 }
 
-var _ mail.Interface = (*mailState)(nil)
+var _ mail.RawInterface = (*mailState)(nil)
 
 func (m *mailState) Send(msg *mail.Message) error {
-        return m.run(func() error { return m.Interface.Send(msg) })
+        return m.run(func() error { return m.RawInterface.Send(msg) })
 }
 
 func (m *mailState) SendToAdmins(msg *mail.Message) error {
-        return m.run(func() error { return m.Interface.SendToAdmins(msg) })
+        return m.run(func() error { return m.RawInterface.SendToAdmins(msg) })
 }
 
 // FilterMail installs a featureBreaker mail filter in the context.
 func FilterMail(c context.Context, defaultError error) (context.Context, FeatureBreaker) {
         state := newState(defaultError)
-        return mail.AddFilters(c, func(ic context.Context, i mail.Interface) mail.Interface {
+        return mail.AddFilters(c, func(ic context.Context, i mail.RawInterface) mail.RawInterface {
                 return &mailState{state, i}
         }), state
 }