internal/proto: rename method calls

CL/172238 renames some protoreflect methods. Make equivalent changes in v1.

Change-Id: Iaa9af9adf864edefeb4d5ec7670efe07290f2890
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/172582
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/go.mod b/go.mod
index 38299ad..eba613e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module github.com/golang/protobuf
 
-require github.com/golang/protobuf/v2 v2.0.0-20190416222953-ab61d41ec93f
+require github.com/golang/protobuf/v2 v2.0.0-20190420063524-d24bc72368a2
diff --git a/go.sum b/go.sum
index 8931984..d5b74bf 100644
--- a/go.sum
+++ b/go.sum
@@ -1,7 +1,9 @@
 github.com/golang/protobuf v1.2.1-0.20190322195920-d94fb84e04b7/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.2.1-0.20190326022002-be03c15fcaa2/go.mod h1:rZ4veVXHB1S2+o7TKqD9Isxml062IeDutnCDtFPUlCc=
+github.com/golang/protobuf v1.2.1-0.20190416233244-13cf6e79fd39/go.mod h1:RgnTNLHWo9HXezTFX5MTeuXnXx9eeQX8y3Cukv+9HaE=
 github.com/golang/protobuf/v2 v2.0.0-20190322201422-f503c300f70e/go.mod h1:25ZALhydMFaBRgPH58a8zpFe9YXMAMjOYWtB6pNPcoo=
-github.com/golang/protobuf/v2 v2.0.0-20190416222953-ab61d41ec93f h1:/ykGaIiod920llcsrLlxw+U2sJkPdzwWF+zABcffzHc=
 github.com/golang/protobuf/v2 v2.0.0-20190416222953-ab61d41ec93f/go.mod h1:baUT2weUsA1MR7ocRtLXLmi2B1s4VrUT3S6tO8AYzMw=
+github.com/golang/protobuf/v2 v2.0.0-20190420063524-d24bc72368a2 h1:Tp4FhirEYFiZdhirylriHTC/4tGUz3j1r96XDMpYaAQ=
+github.com/golang/protobuf/v2 v2.0.0-20190420063524-d24bc72368a2/go.mod h1:wcEMLTNPNYxBFS3yY7kunR0QKUgP/f+wzZaPeTbHi0g=
 github.com/google/go-cmp v0.2.1-0.20190312032427-6f77996f0c42 h1:q3pnF5JFBNRz8sRD+IRj7Y6DMyYGTNqnZ9axTbSfoNI=
 github.com/google/go-cmp v0.2.1-0.20190312032427-6f77996f0c42/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
diff --git a/internal/proto/defaults.go b/internal/proto/defaults.go
index 580d762..c2a0077 100644
--- a/internal/proto/defaults.go
+++ b/internal/proto/defaults.go
@@ -49,7 +49,7 @@
 			}
 		// Handle map of messages.
 		default:
-			k := fd.MessageType().Fields().ByNumber(2).Kind()
+			k := fd.Message().Fields().ByNumber(2).Kind()
 			if k == pref.MessageKind || k == pref.GroupKind {
 				ms := knownFields.Get(num).Map()
 				ms.Range(func(_ pref.MapKey, v pref.Value) bool {
diff --git a/internal/proto/discard.go b/internal/proto/discard.go
index f995cad..2bb0128 100644
--- a/internal/proto/discard.go
+++ b/internal/proto/discard.go
@@ -51,7 +51,7 @@
 			}
 		// Handle map of messages.
 		default:
-			k := fd.MessageType().Fields().ByNumber(2).Kind()
+			k := fd.Message().Fields().ByNumber(2).Kind()
 			if k == pref.MessageKind || k == pref.GroupKind {
 				ms := knownFields.Get(num).Map()
 				ms.Range(func(_ pref.MapKey, v pref.Value) bool {