Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/src/google/protobuf/proto_cast.h

Index: third_party/protobuf/src/google/protobuf/proto_cast.h
diff --git a/third_party/protobuf/src/google/protobuf/proto_cast.h b/third_party/protobuf/src/google/protobuf/proto_cast.h
deleted file mode 100644
index e25c219ffece24b132fa9f9f6280186efba50cf2..0000000000000000000000000000000000000000
--- a/third_party/protobuf/src/google/protobuf/proto_cast.h
+++ /dev/null
@@ -1,58 +0,0 @@
-// 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.
-//     * 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
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// 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_UTIL_PROTO_CAST_H__
-#define GOOGLE_PROTOBUF_UTIL_PROTO_CAST_H__
-
-#include <string>
-
-#include <google/protobuf/stubs/common.h>
-
-// proto_cast<> is used to simulate over-the-wire conversion of one
-// proto message into another.  This is primarily useful for unit tests
-// which validate the version-compatibility semantics of protobufs.
-// Usage is similar to C++-style typecasts:
-//
-// OldMessage old_message = /*...*/;
-// NewMessage new_message = proto_cast<NewMessage>(old_message);
-namespace google {
-template<typename NewProto,
-         typename OldProto>
-NewProto proto_cast(const OldProto& old_proto) {
-  string wire_format;
-  GOOGLE_CHECK(old_proto.SerializeToString(&wire_format));
-
-  NewProto new_proto;
-  GOOGLE_CHECK(new_proto.ParseFromString(wire_format));
-  return new_proto;
-}
-
-}  // namespace google
-#endif  // GOOGLE_PROTOBUF_UTIL_PROTO_CAST_H__