Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/stubs/atomic_sequence_num.h

Index: third_party/protobuf/src/google/protobuf/stubs/atomic_sequence_num.h
diff --git a/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.cc b/third_party/protobuf/src/google/protobuf/stubs/atomic_sequence_num.h
similarity index 76%
copy from third_party/protobuf/src/google/protobuf/io/zero_copy_stream.cc
copy to third_party/protobuf/src/google/protobuf/stubs/atomic_sequence_num.h
index dad6ff14468d031f16baafb2f1ca567961251c43..bb20942f2f77041df602544a8e888341e46feb4b 100644
--- a/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.cc
+++ b/third_party/protobuf/src/google/protobuf/stubs/atomic_sequence_num.h
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// Copyright 2014 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
@@ -27,22 +27,28 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#ifndef GOOGLE_PROTOBUF_ATOMIC_SEQUENCE_NUM_H_
+#define GOOGLE_PROTOBUF_ATOMIC_SEQUENCE_NUM_H_
 
-// Author: kenton@google.com (Kenton Varda)
-//  Based on original Protocol Buffers design by
-//  Sanjay Ghemawat, Jeff Dean, and others.
-
-#include <google/protobuf/io/zero_copy_stream.h>
-
+#include <google/protobuf/stubs/atomicops.h>
 
 namespace google {
 namespace protobuf {
-namespace io {
+namespace internal {
 
-ZeroCopyInputStream::~ZeroCopyInputStream() {}
-ZeroCopyOutputStream::~ZeroCopyOutputStream() {}
+class SequenceNumber {
+ public:
+  SequenceNumber() : word_(0) {}
 
+  AtomicWord GetNext() {
+    return NoBarrier_AtomicIncrement(&word_, 1) - 1;
+  }
+ private:
+  AtomicWord word_;
+};
 
-}  // namespace io
+}  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_ATOMIC_SEQUENCE_NUM_H_