Pull new version of protobuf sources.

third_party/protobuf/src/google/protobuf/io/zero_copy_stream.h

Index: third_party/protobuf/src/google/protobuf/io/zero_copy_stream.h
diff --git a/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.h b/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.h
index db5326f703dbe2239488d8a1495da25971892d8d..52650fc6686d50bbaa70b038b2bef8f04de7c435 100644
--- a/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.h
+++ b/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.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/
+// 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
@@ -226,6 +226,16 @@ class LIBPROTOBUF_EXPORT ZeroCopyOutputStream {
   // Returns the total number of bytes written since this object was created.
   virtual int64 ByteCount() const = 0;
 
+  // Write a given chunk of data to the output.  Some output streams may
+  // implement this in a way that avoids copying. Check AllowsAliasing() before
+  // calling WriteAliasedRaw(). It will GOOGLE_CHECK fail if WriteAliasedRaw() is
+  // called on a stream that does not allow aliasing.
+  //
+  // NOTE: It is caller's responsibility to ensure that the chunk of memory
+  // remains live until all of the data has been consumed from the stream.
+  virtual bool WriteAliasedRaw(const void* data, int size);
+  virtual bool AllowsAliasing() const { return false; }
+
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ZeroCopyOutputStream);