[api] Prototype WeakRef implementation

src/objects-printer.cc

Index: src/objects-printer.cc
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index b4fbb4db15363561f35b37debaefa1ce0ab8c74f..b38217fd0be8d5c1f66d8b8663698ce6e71a085c 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -207,6 +207,9 @@ void HeapObject::HeapObjectPrint(std::ostream& os) {  // NOLINT
     case JS_WEAK_SET_TYPE:
       JSWeakSet::cast(this)->JSWeakSetPrint(os);
       break;
+    case JS_WEAK_REF_TYPE:
+      JSWeakRef::cast(this)->JSWeakRefPrint(os);
+      break;
     case JS_MODULE_NAMESPACE_TYPE:
       JSModuleNamespace::cast(this)->JSModuleNamespacePrint(os);
       break;
@@ -947,6 +950,13 @@ void JSWeakSet::JSWeakSetPrint(std::ostream& os) {  // NOLINT
 }
 
 
+void JSWeakRef::JSWeakRefPrint(std::ostream& os) {  // NOLINT
+  JSObjectPrintHeader(os, this, "JSWeakRef");
+  os << "\n - table = " << Brief(table());
+  JSObjectPrintBody(os, this);
+}
+
+
 void JSArrayBuffer::JSArrayBufferPrint(std::ostream& os) {  // NOLINT
   JSObjectPrintHeader(os, this, "JSArrayBuffer");
   os << "\n - backing_store = " << backing_store();