Correctly track lifetime of promise rejection events

Source/bindings/core/v8/custom/V8PromiseRejectionEventCustom.cpp

Index: Source/bindings/core/v8/custom/V8PromiseRejectionEventCustom.cpp
diff --git a/Source/bindings/core/v8/custom/V8PromiseRejectionEventCustom.cpp b/Source/bindings/core/v8/custom/V8PromiseRejectionEventCustom.cpp
index e38f04cd07c2f28be04c6d9dc4b0f92057e3fdfb..34f289522a8577d5b885bda239146e7d5abf09ad 100644
--- a/Source/bindings/core/v8/custom/V8PromiseRejectionEventCustom.cpp
+++ b/Source/bindings/core/v8/custom/V8PromiseRejectionEventCustom.cpp
@@ -8,6 +8,7 @@
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/ScriptValue.h"
+#include "bindings/core/v8/ScriptWrappable.h"
 #include "bindings/core/v8/V8Binding.h"
 
 namespace blink {
@@ -25,4 +26,10 @@ void V8PromiseRejectionEvent::promiseAttributeGetterCustom(const v8::FunctionCal
     v8SetReturnValue(info, promise.v8Value());
 }
 
+void V8PromiseRejectionEvent::visitDOMWrapper(v8::Isolate* isolate, ScriptWrappable* scriptWrappable, const v8::Persistent<v8::Object>& wrapper)
+{
+    PromiseRejectionEvent* event = scriptWrappable->toImpl<PromiseRejectionEvent>();
+    event->setWrapperReference(isolate, wrapper);
+}
+
 } // namespace blink