Update //third_party/protobuf to version 3.

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

Index: third_party/protobuf/src/google/protobuf/io/strtod.h
diff --git a/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.cc b/third_party/protobuf/src/google/protobuf/io/strtod.h
similarity index 71%
copy from third_party/protobuf/src/google/protobuf/io/zero_copy_stream.cc
copy to third_party/protobuf/src/google/protobuf/io/strtod.h
index dad6ff14468d031f16baafb2f1ca567961251c43..f56e41c8403087316fea469a5803509a452a787a 100644
--- a/third_party/protobuf/src/google/protobuf/io/zero_copy_stream.cc
+++ b/third_party/protobuf/src/google/protobuf/io/strtod.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
@@ -28,21 +28,28 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// 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>
+// A locale-independent version of strtod(), used to parse floating
+// point default values in .proto files, where the decimal separator
+// is always a dot.
 
+#ifndef GOOGLE_PROTOBUF_IO_STRTOD_H__
+#define GOOGLE_PROTOBUF_IO_STRTOD_H__
 
 namespace google {
 namespace protobuf {
 namespace io {
 
-ZeroCopyInputStream::~ZeroCopyInputStream() {}
-ZeroCopyOutputStream::~ZeroCopyOutputStream() {}
+// A locale-independent version of the standard strtod(), which always
+// uses a dot as the decimal separator.
+double NoLocaleStrtod(const char* str, char** endptr);
 
+// Casts a double value to a float value. If the value is outside of the
+// representable range of float, it will be converted to positive or negative
+// infinity.
+float SafeDoubleToFloat(double value);
 
 }  // namespace io
 }  // namespace protobuf
+
 }  // namespace google
+#endif  // GOOGLE_PROTOBUF_IO_STRTOD_H__