Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/src/google/protobuf/util/internal/testdata/books.proto

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // 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.
@@ skipping 38 matching lines @@
   }
 
   message Label {
     optional string key = 1;
     optional string value = 2;
   }
 
   optional Publisher publisher = 9;
   repeated Label labels = 10;
 
+  enum Type {
+    FICTION = 1;
+    KIDS = 2;
+    ACTION_AND_ADVENTURE = 3;
+  }
+  optional Type type = 11;
+
   extensions 200 to 499;
 }
 
 // A publisher of a book, tests required fields.
 message Publisher {
   required string name = 1;
 }
 
 // An author of a book
 message Author {
@@ skipping 93 matching lines @@
   }
   // Recurse
   optional Book book = 1;
 }
 
 // For testing resiliency of our protostream parser.
 // Field number of NestedBook is reused for something else.
 message BadNestedBook {
   repeated uint32 book = 1 [packed=true];  // Packed to optional message.
 }
+
+// A recursively defined message.
+message Cyclic {
+  optional int32 m_int = 1;
+  optional string m_str = 2;
+  optional Book m_book = 3;
+  repeated Author m_author = 5;
+  optional Cyclic m_cyclic = 4;
+}