Make json_proto::JsonObject contain arbitrary number of fields

Change-Id: I7c6ea9c7742d67d0e2eb0d365757558818001a3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2418987
Commit-Queue: Dan McArdle <dmcardle@chromium.org>
Reviewed-by: Jonathan Metzman <metzman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810218}

testing/libfuzzer/proto/json.proto

@@ -9,11 +9,15 @@ syntax = "proto2";
 
 package json_proto;
 
-message JsonObject {
+message JsonObjectField {
   required string name = 1;
   required JsonValue value = 2;
 }
 
+message JsonObject {
+  repeated JsonObjectField field = 3;
+}
+
 message JsonValue {
   oneof value {
     // Json value types:

testing/libfuzzer/proto/json_proto_converter.cc

@@ -40,8 +40,16 @@ void JsonProtoConverter::AppendNumber(const NumberValue& number_value) {
 }
 
 void JsonProtoConverter::AppendObject(const JsonObject& json_object) {
-  data_ << '{' << '"' << json_object.name() << '"' << ':';
-  AppendValue(json_object.value());
+  data_ << '{';
+  bool leading_comma = false;
+  for (const auto& field : json_object.field()) {
+    if (leading_comma) {
+      data_ << ",";
+    }
+    leading_comma = true;
+    data_ << '"' << field.name() << '"' << ':';
+    AppendValue(field.value());
+  }
   data_ << '}';
 }
 

testing/libfuzzer/proto/json_proto_converter.h

@@ -14,6 +14,7 @@ namespace json_proto {
 
 class JsonProtoConverter {
  public:
+  std::string Convert(const JsonValue& json_value);
   std::string Convert(const json_proto::JsonObject&);
   std::string Convert(const json_proto::ArrayValue&);