Make HTTP middleware easier to use

appengine/cmd/helloworld_mvm/backend/main.go

Index: appengine/cmd/helloworld_mvm/backend/main.go
diff --git a/appengine/cmd/helloworld_mvm/backend/main.go b/appengine/cmd/helloworld_mvm/backend/main.go
index 23e62c89f6ed29985ff19d978aad7e5ddbdc5219..138e837fed040fd90ff10c36bad0eda1872c440b 100644
--- a/appengine/cmd/helloworld_mvm/backend/main.go
+++ b/appengine/cmd/helloworld_mvm/backend/main.go
@@ -9,25 +9,23 @@ package main
 import (
 	"net/http"
 
-	"github.com/julienschmidt/httprouter"
-	"golang.org/x/net/context"
 	"google.golang.org/appengine"
 
 	"github.com/luci/luci-go/appengine/gaemiddleware"
-	"github.com/luci/luci-go/server/middleware"
+	"github.com/luci/luci-go/server/router"
 )
 
 // base is the root of the middleware chain.
-func base(h middleware.Handler) httprouter.Handle {
-	return gaemiddleware.BaseProd(h)
+func base() []router.Handler {
+	return gaemiddleware.BaseProd()
 }
 
 //// Routes.
 
 func main() {
-	router := httprouter.New()
-	gaemiddleware.InstallHandlers(router, base)
-	router.GET("/hi", base(sayHi))
+	router := router.New()
+	gaemiddleware.InstallHandlers(router, base())
+	router.GET("/hi", append(base(), sayHi)...)
 	http.DefaultServeMux.Handle("/", router)
 
 	appengine.Main()
@@ -35,6 +33,6 @@ func main() {
 
 //// Handlers.
 
-func sayHi(c context.Context, w http.ResponseWriter, r *http.Request, p httprouter.Params) {
-	w.Write([]byte("Hi, I'm backend"))
+func sayHi(c *router.Context) {
+	c.Writer.Write([]byte("Hi, I'm backend"))
 }