Make HTTP middleware easier to use

appengine/gaemiddleware/routes.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 gaemiddleware
 
 import (
-        "github.com/julienschmidt/httprouter"
-        "github.com/luci/luci-go/server/middleware"
+        "github.com/luci/luci-go/server/router"
         "github.com/luci/luci-go/server/settings/admin"
 
         gaeauth "github.com/luci/luci-go/appengine/gaeauth/server"
         "github.com/luci/luci-go/appengine/tsmon"
 )
 
 // InstallHandlers installs HTTP handlers for various default routes.
 //
 // These routes are needed for various services provided in BaseProd context to
 // work (e.g. authentication related routes, time series monitoring, etc).
 //
 // 'base' is expected to be BaseProd or its derivative.
-func InstallHandlers(r *httprouter.Router, base middleware.Base) {
-        gaeauth.InstallWebHandlers(r, base)
+func InstallHandlers(r *router.Router, base router.MiddlewareChain) {
+        gaeauth.InstallHandlers(r, base)
         tsmon.InstallHandlers(r, base)
         admin.InstallHandlers(r, base, &gaeauth.UsersAPIAuthMethod{})
 }