Add a MustNamespace that panics if the namespace wasn't valid

filter/featureBreaker/gi.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package featureBreaker
 
 import (
         "time"
 
         "golang.org/x/net/context"
@@ skipping 24 matching lines @@
 }
 
 func (g *infoState) Namespace(namespace string) (ret context.Context, err error) {
         err = g.run(func() (err error) {
                 ret, err = g.Interface.Namespace(namespace)
                 return
         })
         return
 }
 
+func (g *infoState) MustNamespace(namespace string) context.Context {
+        ret, err := g.Namespace(namespace)
+        if err != nil {
+                panic(err)
+        }
+        return ret
+}
+
 func (g *infoState) AccessToken(scopes ...string) (token string, expiry time.Time, err error) {
         err = g.run(func() (err error) {
                 token, expiry, err = g.Interface.AccessToken(scopes...)
                 return
         })
         return
 }
 
 func (g *infoState) PublicCertificates() (ret []info.Certificate, err error) {
         err = g.run(func() (err error) {
@@ skipping 11 matching lines @@
         return
 }
 
 // FilterGI installs a counter info filter in the context.
 func FilterGI(c context.Context, defaultError error) (context.Context, FeatureBreaker) {
         state := newState(defaultError)
         return info.AddFilters(c, func(ic context.Context, i info.Interface) info.Interface {
                 return &infoState{state, i}
         }), state
 }