Throw exceptions for errors in v8::ValueSerializer.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 0dfe70d5dd69c973e060ff636da8a7bf00385835..6482c45db552e4a5b41a9356da803590f9906241 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -2838,13 +2838,18 @@ MaybeLocal<String> JSON::Stringify(Local<Context> context,
 // --- V a l u e   S e r i a l i z a t i o n ---
 
 struct ValueSerializer::PrivateData {
-  explicit PrivateData(i::Isolate* i) : isolate(i), serializer(i) {}
+  explicit PrivateData(i::Isolate* i, ValueSerializer::Delegate* delegate)
+      : isolate(i), serializer(i, delegate) {}
   i::Isolate* isolate;
   i::ValueSerializer serializer;
 };
 
 ValueSerializer::ValueSerializer(Isolate* isolate)
-    : private_(new PrivateData(reinterpret_cast<i::Isolate*>(isolate))) {}
+    : ValueSerializer(isolate, nullptr) {}
+
+ValueSerializer::ValueSerializer(Isolate* isolate, Delegate* delegate)
+    : private_(
+          new PrivateData(reinterpret_cast<i::Isolate*>(isolate), delegate)) {}
 
 ValueSerializer::~ValueSerializer() { delete private_; }