Make HTTP middleware easier to use

appengine/gaeauth/server/default.go

Index: appengine/gaeauth/server/default.go
diff --git a/appengine/gaeauth/server/default.go b/appengine/gaeauth/server/default.go
index 937f3f23906dc6414d80ca09ab93f4b36f4900f8..470b9a0f16b222214f435401de7191c748ca8a8f 100644
--- a/appengine/gaeauth/server/default.go
+++ b/appengine/gaeauth/server/default.go
@@ -8,7 +8,6 @@ import (
 	"runtime"
 	"strings"
 
-	"github.com/julienschmidt/httprouter"
 	"golang.org/x/net/context"
 	"google.golang.org/appengine"
 
@@ -17,7 +16,7 @@ import (
 	"github.com/luci/luci-go/server/auth/info"
 	"github.com/luci/luci-go/server/auth/openid"
 	"github.com/luci/luci-go/server/auth/signing"
-	"github.com/luci/luci-go/server/middleware"
+	"github.com/luci/luci-go/server/router"
 
 	"github.com/luci/luci-go/appengine/gaeauth/server/internal/authdb"
 )
@@ -36,7 +35,7 @@ var CookieAuth auth.Method
 //
 // TODO(vadimsh): Rename to InstallHandlers after June 1 2016. It was renamed
 // to purposely break code that called it (since its semantics has changed).
-func InstallWebHandlers(r *httprouter.Router, base middleware.Base) {
+func InstallWebHandlers(r *router.Router, base router.MiddlewareChain) {
 	m := CookieAuth.(cookieAuthMethod)
 	if oid, ok := m.Method.(*openid.AuthMethod); ok {
 		oid.InstallHandlers(r, base)