[api] Prototype WeakRef implementation

src/heap/objects-visiting.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/objects-visiting.h"
 
 #include "src/heap/heap-inl.h"
 #include "src/heap/mark-compact-inl.h"
 #include "src/heap/objects-visiting-inl.h"
 
@@ skipping 71 matching lines @@
     case WEAK_CELL_TYPE:
       return kVisitWeakCell;
 
     case TRANSITION_ARRAY_TYPE:
       return kVisitTransitionArray;
 
     case JS_WEAK_MAP_TYPE:
     case JS_WEAK_SET_TYPE:
       return kVisitJSWeakCollection;
 
+    case JS_WEAK_REF_TYPE:
+      return kVisitJSWeakRef;
+
     case JS_REGEXP_TYPE:
       return kVisitJSRegExp;
 
     case SHARED_FUNCTION_INFO_TYPE:
       return kVisitSharedFunctionInfo;
 
     case JS_PROXY_TYPE:
       return kVisitStruct;
 
     case SYMBOL_TYPE:
@@ skipping 292 matching lines @@
 };
 
 
 template Object* VisitWeakList<Context>(Heap* heap, Object* list,
                                         WeakObjectRetainer* retainer);
 
 template Object* VisitWeakList<AllocationSite>(Heap* heap, Object* list,
                                                WeakObjectRetainer* retainer);
 }  // namespace internal
 }  // namespace v8