Update //third_party/protobuf to version 3.

third_party/protobuf/patches/0002-remove-support-for-unnecessary-languages.patch

Index: third_party/protobuf/patches/0002-remove-support-for-unnecessary-languages.patch
diff --git a/third_party/protobuf/patches/0002-remove-support-for-unnecessary-languages.patch b/third_party/protobuf/patches/0002-remove-support-for-unnecessary-languages.patch
new file mode 100644
index 0000000000000000000000000000000000000000..83a667a35320d6493ae976fcc1ed15fc9eeb060b
--- /dev/null
+++ b/third_party/protobuf/patches/0002-remove-support-for-unnecessary-languages.patch
@@ -0,0 +1,57 @@
+--- protobuf-cleaned/src/google/protobuf/compiler/main.cc	2015-12-30 13:21:46.000000000 -0800
++++ protobuf-patched/src/google/protobuf/compiler/main.cc	2016-03-31 13:25:41.548005626 -0700
+@@ -33,12 +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>
+-#include <google/protobuf/compiler/javanano/javanano_generator.h>
+-#include <google/protobuf/compiler/ruby/ruby_generator.h>
+-#include <google/protobuf/compiler/csharp/csharp_generator.h>
+-#include <google/protobuf/compiler/objectivec/objectivec_generator.h>
+-#include <google/protobuf/compiler/js/js_generator.h>
+ 
+ int main(int argc, char* argv[]) {
+ 
+@@ -50,41 +44,10 @@
+   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,
+                         "Generate Python source file.");
+ 
+-  // Java Nano
+-  google::protobuf::compiler::javanano::JavaNanoGenerator javanano_generator;
+-  cli.RegisterGenerator("--javanano_out", &javanano_generator,
+-                        "Generate Java Nano source file.");
+-
+-  // Ruby
+-  google::protobuf::compiler::ruby::Generator rb_generator;
+-  cli.RegisterGenerator("--ruby_out", &rb_generator,
+-                        "Generate Ruby source file.");
+-
+-  // CSharp
+-  google::protobuf::compiler::csharp::Generator csharp_generator;
+-  cli.RegisterGenerator("--csharp_out", "--csharp_opt", &csharp_generator,
+-                        "Generate C# source file.");
+-
+-  // Objective C
+-  google::protobuf::compiler::objectivec::ObjectiveCGenerator objc_generator;
+-  cli.RegisterGenerator("--objc_out", &objc_generator,
+-                        "Generate Objective C header and source.");
+-
+-  // JavaScript
+-  google::protobuf::compiler::js::Generator js_generator;
+-  cli.RegisterGenerator("--js_out", &js_generator,
+-                        "Generate JavaScript source.");
+-
+   return cli.Run(argc, argv);
+ }