Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/compiler/java/java_generator.h

 // 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
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
@@ skipping 49 matching lines @@
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(JavaGenerator);
 };
 
 }  // namespace java
 }  // namespace compiler
 }  // namespace protobuf
 
 }  // namespace google
 #endif  // GOOGLE_PROTOBUF_COMPILER_JAVA_GENERATOR_H__