Revert of Migrate tsmon protos to proto3

appengine/tsmon/middleware_test.go

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package tsmon
 
 import (
         "net/http"
         "net/http/httptest"
         "testing"
         "time"
 
+        "github.com/golang/protobuf/proto"
         "github.com/julienschmidt/httprouter"
         "github.com/luci/gae/service/datastore"
         "github.com/luci/luci-go/common/tsmon"
         "github.com/luci/luci-go/common/tsmon/field"
         "github.com/luci/luci-go/common/tsmon/monitor"
         "github.com/luci/luci-go/common/tsmon/store"
         "github.com/luci/luci-go/common/tsmon/target"
         "github.com/luci/luci-go/common/tsmon/types"
         "golang.org/x/net/context"
 
@@ skipping 74 matching lines @@
 
                 lastFlushed.Time = clock.Now().Add(-2 * time.Minute)
 
                 rec := httptest.NewRecorder()
                 Middleware(func(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
                         f(c, rw, r, p)
 
                         // Override the TaskNum here - it's created just before this handler runs
                         // and used just after.
                         tar := tsmon.Store(c).DefaultTarget().(*target.Task)
-                        tar.TaskNum = 0
+                        tar.TaskNum = proto.Int32(int32(0))
                         tsmon.Store(c).SetDefaultTarget(tar)
                 })(c, rec, &http.Request{}, nil)
                 So(rec.Code, ShouldEqual, http.StatusOK)
 
                 So(len(tsmon.GetState(c).RegisteredMetrics), ShouldEqual, 1)
 
                 monitor := tsmon.GetState(c).M.(*monitor.Fake)
                 So(len(monitor.Cells), ShouldEqual, 0)
 
                 // Value should be reset.
                 value, err := tsmon.Store(c).Get(c, metric, time.Time{}, []interface{}{})
                 So(err, ShouldBeNil)
                 So(value, ShouldBeNil)
         })
 }