Make HTTP middleware easier to use

appengine/tsmon/global_callback_test.go

Index: appengine/tsmon/global_callback_test.go
diff --git a/appengine/tsmon/global_callback_test.go b/appengine/tsmon/global_callback_test.go
index 0fb98c08efb54b865d78af650b2559a56eadf344..e88a7a30902910219193735eed204c9d90976675 100644
--- a/appengine/tsmon/global_callback_test.go
+++ b/appengine/tsmon/global_callback_test.go
@@ -10,11 +10,11 @@ import (
 	"testing"
 	"time"
 
-	"github.com/julienschmidt/httprouter"
 	"github.com/luci/gae/service/datastore"
 	"github.com/luci/luci-go/common/clock"
 	"github.com/luci/luci-go/common/tsmon"
 	"github.com/luci/luci-go/common/tsmon/metric"
+	"github.com/luci/luci-go/server/router"
 	"golang.org/x/net/context"
 
 	. "github.com/smartystreets/goconvey/convey"
@@ -33,7 +33,9 @@ func flushNowWithMiddleware(c context.Context, state *State) {
 	state.lastFlushed = clock.Now(c).Add(-2 * time.Minute)
 
 	rec := httptest.NewRecorder()
-	state.Middleware(func(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {})(c, rec, &http.Request{}, nil)
+	router.ChainHandlers(func(ctx *router.Context) {
+		ctx.Context, ctx.Writer, ctx.Request = c, rec, &http.Request{}
+	}, state.Middleware())()
 	So(rec.Code, ShouldEqual, http.StatusOK)
 }
 
@@ -60,7 +62,9 @@ func TestGlobalCallbacks(t *testing.T) {
 			s := tsmon.Store(c)
 
 			rec := httptest.NewRecorder()
-			housekeepingHandler(c, rec, &http.Request{}, nil)
+			router.ChainHandlers(func(ctx *router.Context) {
+				ctx.Context, ctx.Writer, ctx.Request = c, rec, &http.Request{}
+			}, housekeepingHandler)()
 			So(rec.Code, ShouldEqual, http.StatusOK)
 
 			val, err := s.Get(c, m, time.Time{}, []interface{}{})