[api] Prototype WeakRef implementation

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index f6ec4f398e04453e6eb5f0ab1db2d1bf9b548774..6bf603f1f4ed72376ca854315e7f69f6d75de885 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -216,6 +216,9 @@ void HeapObject::HeapObjectVerify() {
     case JS_WEAK_SET_TYPE:
       JSWeakSet::cast(this)->JSWeakSetVerify();
       break;
+    case JS_WEAK_REF_TYPE:
+      JSWeakRef::cast(this)->JSWeakRefVerify();
+      break;
     case JS_PROMISE_CAPABILITY_TYPE:
       JSPromiseCapability::cast(this)->JSPromiseCapabilityVerify();
       break;
@@ -969,6 +972,12 @@ void JSWeakSet::JSWeakSetVerify() {
   VerifyHeapPointer(table());
   CHECK(table()->IsHashTable() || table()->IsUndefined(GetIsolate()));
 }
+void JSWeakRef::JSWeakRefVerify() {
+  CHECK(IsJSWeakRef());
+  JSObjectVerify();
+  VerifyHeapPointer(table());
+  CHECK(table()->IsHashTable() || table()->IsUndefined(GetIsolate()));
+}
 
 void JSPromiseCapability::JSPromiseCapabilityVerify() {
   CHECK(IsJSPromiseCapability());