runtime/protolegacy: remove package

The legacy logic has now been merged into impl.

Change-Id: I999dfa2b7f49cbd98614a54d8ec70e611a3d033a
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/178544
Reviewed-by: Damien Neil <dneil@google.com>

go.mod

@@ -3,6 +3,6 @@ module google.golang.org/protobuf
 go 1.9
 
 require (
-	github.com/golang/protobuf v1.2.1-0.20190516215712-ae2eaafab405
+	github.com/golang/protobuf v1.2.1-0.20190523175523-a1331f0b4ab4
 	github.com/google/go-cmp v0.3.0
 )

go.sum

@@ -1,11 +1,13 @@
 github.com/golang/protobuf v1.2.1-0.20190514181236-7800af189d76/go.mod h1:Zfz6qcDoDBESdv6JsKsGpgNHnkvwJAJwcA9eL+mOkgc=
 github.com/golang/protobuf v1.2.1-0.20190515194842-7574ba03306e/go.mod h1:GjgUz9uwrRQmdPBBrFqiVbojAmlpy6ryM6DCzC+20rE=
 github.com/golang/protobuf v1.2.1-0.20190516201927-a2cd3ac1b343/go.mod h1:PScGDF2x230A126tLt9Ol9RjhXzbiPJrt/CogooD2mE=
-github.com/golang/protobuf v1.2.1-0.20190516215712-ae2eaafab405 h1:j0K4x4UIgNTsXHO1mjIWLGLVyvq1tcfhurSmgbnMTE4=
 github.com/golang/protobuf v1.2.1-0.20190516215712-ae2eaafab405/go.mod h1:UmP8hhPKR5WWIjbT9v0JEVT+U0DBSjbW8KaZVeyFfRE=
+github.com/golang/protobuf v1.2.1-0.20190523175523-a1331f0b4ab4 h1:266Mauktp82G9qvMyYdGtx+yv9kmSkBSVw2BOgK8578=
+github.com/golang/protobuf v1.2.1-0.20190523175523-a1331f0b4ab4/go.mod h1:G+fNMoyvKWZDB7PCDHF+dXbH9OeE3+JoozCd9V7i66U=
 github.com/google/go-cmp v0.3.0 h1:crn/baboCvb5fXaQ0IJ1SGTsTVrWpDsCWC8EGETZijY=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 google.golang.org/protobuf v0.0.0-20190514172829-e89e6244e0e8/go.mod h1:791zQGC15vDqjpmPRn1uGPu5oHy/Jzw/Q1n5JsgIIcY=
 google.golang.org/protobuf v0.0.0-20190514231807-cdb777356907/go.mod h1:HeRLsKXv4+wE27dOIGwnqcOgq6a1O/GJ7mGhiEPnBrU=
 google.golang.org/protobuf v0.0.0-20190516201745-40b83d67fc75/go.mod h1:jf+u8AHuKtkib+0J4/bQXPNzCmT3V9a02hVzYKtatuw=
 google.golang.org/protobuf v0.0.0-20190516215540-a95b29fbf623/go.mod h1:cWWmz5lsCWIcqGLROrKq5Lu231IJw2PzqOZ8cgspbfY=
+google.golang.org/protobuf v0.0.0-20190522194032-21ade498bd69/go.mod h1:cJytyYi/6qdwy/+gD49hmgHcwD7zhWxE/1KPEslaZ3M=

proto/decode_test.go

@@ -16,7 +16,7 @@ import (
 	"google.golang.org/protobuf/internal/scalar"
 	"google.golang.org/protobuf/proto"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
-	"google.golang.org/protobuf/runtime/protolegacy"
+	"google.golang.org/protobuf/runtime/protoimpl"
 
 	legacypb "google.golang.org/protobuf/internal/testprotos/legacy"
 	legacy1pb "google.golang.org/protobuf/internal/testprotos/legacy/proto2.v0.0.0-20160225-2fc053c5"
@@ -1353,7 +1353,7 @@ func unknown(num pref.FieldNumber, raw pref.RawFields) buildOpt {
 
 func registerExtension(desc *protoV1.ExtensionDesc) buildOpt {
 	return func(m proto.Message) {
-		et := protolegacy.X.ExtensionTypeFromDesc(desc)
+		et := protoimpl.X.ExtensionTypeFromDesc(desc)
 		m.ProtoReflect().KnownFields().ExtensionTypes().Register(et)
 	}
 }

runtime/protolegacy/legacy.go

@@ -1,12 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Deprecated: Do not use.
-package protolegacy
-
-// TODO: Remove this.
-
-import "google.golang.org/protobuf/internal/impl"
-
-var X impl.Export