goprotobuf: Cause the descriptor proto to be imported as "descriptor".

LGTM=gmlewis
R=gmlewis
CC=golang-codereviews
https://codereview.appspot.com/160730043

proto/testdata/test.pb.go

@@ -1416,6 +1416,12 @@ func (m *MyMessageSet) Marshal() ([]byte, error) {
 func (m *MyMessageSet) Unmarshal(buf []byte) error {
 	return proto.UnmarshalMessageSet(buf, m.ExtensionMap())
 }
+func (m *MyMessageSet) MarshalJSON() ([]byte, error) {
+	return proto.MarshalMessageSetJSON(m.XXX_extensions)
+}
+func (m *MyMessageSet) UnmarshalJSON(buf []byte) error {
+	return proto.UnmarshalMessageSetJSON(buf, m.XXX_extensions)
+}
 
 // ensure MyMessageSet satisfies proto.Marshaler and proto.Unmarshaler
 var _ proto.Marshaler = (*MyMessageSet)(nil)

protoc-gen-go/descriptor/Makefile

@@ -35,6 +35,7 @@ regenerate:
 	echo WARNING! THIS RULE IS PROBABLY NOT RIGHT FOR YOUR INSTALLATION
 	cd $(HOME)/src/protobuf-2.5.0/src && \
 	protoc --go_out=. ./google/protobuf/descriptor.proto && \
+	sed -i 's,^package google_protobuf,package descriptor,' google/protobuf/descriptor.pb.go && \
 	cp ./google/protobuf/descriptor.pb.go $(GOPATH)/src/code.google.com/p/goprotobuf/protoc-gen-go/descriptor/descriptor.pb.go
 
 restore:

protoc-gen-go/descriptor/descriptor.pb.go

@@ -27,7 +27,7 @@ It has these top-level messages:
 	UninterpretedOption
 	SourceCodeInfo
 */
-package google_protobuf
+package descriptor
 
 import proto "code.google.com/p/goprotobuf/proto"
 import math "math"

protoc-gen-go/generator/generator.go

@@ -51,7 +51,8 @@ import (
 	"unicode/utf8"
 
 	"code.google.com/p/goprotobuf/proto"
-	descriptor "code.google.com/p/goprotobuf/protoc-gen-go/descriptor"
+
+	"code.google.com/p/goprotobuf/protoc-gen-go/descriptor"
 	plugin "code.google.com/p/goprotobuf/protoc-gen-go/plugin"
 )