Update APIs to use new Google cloud paths.

grpc/cmd/cproto/discovery.go

 // Copyright 2016 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 main
 
 import (
         "bytes"
         "compress/gzip"
         "fmt"
         "io/ioutil"
         "os"
         "os/exec"
         "strings"
         "text/template"
 
         "github.com/golang/protobuf/proto"
-        "github.com/luci/luci-go/common/proto/google/descriptor"
         "golang.org/x/net/context"
+        "google.golang.org/genproto/protobuf"
 )
 
 const (
         discoveryPackagePath = "github.com/luci/luci-go/grpc/discovery"
 )
 
 // discoveryTmpl is template for generated Go discovery file.
 // The result of execution will also be passed through gofmt.
 var discoveryTmpl = template.Must(template.New("").Parse(strings.TrimSpace(`
 // AUTOGENERATED. DO NOT EDIT.
 
 package {{.GoPkg}};
 
 {{if .ImportDiscovery}}
 import discovery "github.com/luci/luci-go/grpc/discovery"
 {{end}}
-import "github.com/luci/luci-go/common/proto/google/descriptor"
+import "google.golang.org/genproto/protobuf"
 
 func init() {
         {{if .ImportDiscovery}}discovery.{{end}}RegisterDescriptorSetCompressed(
                 []string{
                         {{range .ServiceNames}}"{{.}}",{{end}}
                 },
                 {{.CompressedBytes}},
         )
 }
 
@@ skipping 100 matching lines @@
         var buf bytes.Buffer
         w := gzip.NewWriter(&buf)
         if _, err := w.Write(data); err != nil {
                 return nil, err
         }
         if err := w.Close(); err != nil {
                 return nil, err
         }
         return buf.Bytes(), nil
 }