Make HTTP middleware easier to use

common/prpc/talk/helloworld/frontend/handler.go

Index: common/prpc/talk/helloworld/frontend/handler.go
diff --git a/common/prpc/talk/helloworld/frontend/handler.go b/common/prpc/talk/helloworld/frontend/handler.go
index 328157b5310c984a8e822d775392018e914d659a..aa149074327a76ca97dac3c383078e75660337ae 100644
--- a/common/prpc/talk/helloworld/frontend/handler.go
+++ b/common/prpc/talk/helloworld/frontend/handler.go
@@ -7,16 +7,15 @@ package helloworld
 import (
 	"net/http"
 
-	"github.com/julienschmidt/httprouter"
-
 	"github.com/luci/luci-go/appengine/gaemiddleware"
+	"github.com/luci/luci-go/server/router"
 )
 
 func init() {
-	router := httprouter.New()
-	gaemiddleware.InstallHandlers(router, gaemiddleware.BaseProd)
+	r := router.New()
+	gaemiddleware.InstallHandlers(r, gaemiddleware.BaseProd())
 
-	InstallAPIRoutes(router, gaemiddleware.BaseProd)
+	InstallAPIRoutes(r, gaemiddleware.BaseProd())
 
-	http.DefaultServeMux.Handle("/", router)
+	http.DefaultServeMux.Handle("/", r)
 }