Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/compiler/main.cc

Index: third_party/protobuf/src/google/protobuf/compiler/main.cc
diff --git a/third_party/protobuf/src/google/protobuf/compiler/main.cc b/third_party/protobuf/src/google/protobuf/compiler/main.cc
index 1afc5d611130c70a812c41cbc6e848e45616b269..5218842a9f6cef6b8b7bc595a50eaaa166585c75 100644
--- a/third_party/protobuf/src/google/protobuf/compiler/main.cc
+++ b/third_party/protobuf/src/google/protobuf/compiler/main.cc
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
@@ -33,8 +33,6 @@
 #include <google/protobuf/compiler/command_line_interface.h>
 #include <google/protobuf/compiler/cpp/cpp_generator.h>
 #include <google/protobuf/compiler/python/python_generator.h>
-#include <google/protobuf/compiler/java/java_generator.h>
-
 
 int main(int argc, char* argv[]) {
 
@@ -46,12 +44,6 @@ int main(int argc, char* argv[]) {
   cli.RegisterGenerator("--cpp_out", "--cpp_opt", &cpp_generator,
                         "Generate C++ header and source.");
 
-  // Proto2 Java
-  google::protobuf::compiler::java::JavaGenerator java_generator;
-  cli.RegisterGenerator("--java_out", &java_generator,
-                        "Generate Java source file.");
-
-
   // Proto2 Python
   google::protobuf::compiler::python::Generator py_generator;
   cli.RegisterGenerator("--python_out", &py_generator,