Update //third_party/protobuf to version 3.

third_party/protobuf/examples/list_people.go

+package main
+
+import (
+        "fmt"
+        "io"
+        "io/ioutil"
+        "log"
+        "os"
+
+        "github.com/golang/protobuf/proto"
+        pb "github.com/google/protobuf/examples/tutorial"
+)
+
+func writePerson(w io.Writer, p *pb.Person) {
+        fmt.Fprintln(w, "Person ID:", p.Id)
+        fmt.Fprintln(w, "  Name:", p.Name)
+        if p.Email != "" {
+                fmt.Fprintln(w, "  E-mail address:", p.Email)
+        }
+
+        for _, pn := range p.Phones {
+                switch pn.Type {
+                case pb.Person_MOBILE:
+                        fmt.Fprint(w, "  Mobile phone #: ")
+                case pb.Person_HOME:
+                        fmt.Fprint(w, "  Home phone #: ")
+                case pb.Person_WORK:
+                        fmt.Fprint(w, "  Work phone #: ")
+                }
+                fmt.Fprintln(w, pn.Number)
+        }
+}
+
+func listPeople(w io.Writer, book *pb.AddressBook) {
+        for _, p := range book.People {
+                writePerson(w, p)
+        }
+}
+
+// Main reads the entire address book from a file and prints all the
+// information inside.
+func main() {
+        if len(os.Args) != 2 {
+                log.Fatalf("Usage:  %s ADDRESS_BOOK_FILE\n", os.Args[0])
+        }
+        fname := os.Args[1]
+
+        // [START unmarshal_proto]
+        // Read the existing address book.
+        in, err := ioutil.ReadFile(fname)
+        if err != nil {
+                log.Fatalln("Error reading file:", err)
+        }
+        book := &pb.AddressBook{}
+        if err := proto.Unmarshal(in, book); err != nil {
+                log.Fatalln("Failed to parse address book:", err)
+        }
+        // [END unmarshal_proto]
+
+        listPeople(os.Stdout, book)
+}