third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/util/internal/json_objectwriter.cc

 // 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 129 matching lines @@
   WriteChar('"');
   return this;
 }
 
 JsonObjectWriter* JsonObjectWriter::RenderBytes(StringPiece name,
                                                 StringPiece value) {
   WritePrefix(name);
   string base64;
 
   if (use_websafe_base64_for_bytes_)
-    WebSafeBase64Escape(value.ToString(), &base64);
+    WebSafeBase64EscapeWithPadding(value.ToString(), &base64);
   else
     Base64Escape(value, &base64);
 
   WriteChar('"');
   // TODO(wpoon): Consider a ByteSink solution that writes the base64 bytes
   //              directly to the stream, rather than first putting them
   //              into a string and then writing them to the stream.
   stream_->WriteRaw(base64.data(), base64.size());
   WriteChar('"');
   return this;
 }
 
 JsonObjectWriter* JsonObjectWriter::RenderNull(StringPiece name) {
   return RenderSimple(name, "null");
 }
 
+JsonObjectWriter* JsonObjectWriter::RenderNullAsEmpty(StringPiece name) {
+  return RenderSimple(name, "");
+}
+
 void JsonObjectWriter::WritePrefix(StringPiece name) {
   bool not_first = !element()->is_first();
   if (not_first) WriteChar(',');
   if (not_first || !element()->is_root()) NewLine();
-  if (!name.empty()) {
+  bool empty_key_ok = GetAndResetEmptyKeyOk();
+  if (!name.empty() || empty_key_ok) {
     WriteChar('"');
-    ArrayByteSource source(name);
-    JsonEscaping::Escape(&source, &sink_);
+    if (!name.empty()) {
+      ArrayByteSource source(name);
+      JsonEscaping::Escape(&source, &sink_);
+    }
     stream_->WriteString("\":");
     if (!indent_string_.empty()) WriteChar(' ');
   }
 }
 
+bool JsonObjectWriter::GetAndResetEmptyKeyOk() {
+  bool retval = empty_name_ok_for_next_key_;
+  empty_name_ok_for_next_key_ = false;
+  return retval;
+}
+
 }  // namespace converter
 }  // namespace util
 }  // namespace protobuf
 }  // namespace google