[api] Prototype WeakRef implementation

src/heap/object-stats.h

 // Copyright 2015 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.
 
 #ifndef V8_HEAP_OBJECT_STATS_H_
 #define V8_HEAP_OBJECT_STATS_H_
 
 #include <set>
 
 #include "src/base/ieee754.h"
@@ skipping 130 matching lines @@
  private:
   class CompilationCacheTableVisitor;
 
   void RecordBytecodeArrayDetails(BytecodeArray* obj);
   void RecordCodeDetails(Code* code);
   void RecordFixedArrayDetails(FixedArray* array);
   void RecordJSCollectionDetails(JSObject* obj);
   void RecordJSFunctionDetails(JSFunction* function);
   void RecordJSObjectDetails(JSObject* object);
   void RecordJSWeakCollectionDetails(JSWeakCollection* obj);
+  void RecordJSWeakRefDetails(JSWeakRef* obj);
   void RecordMapDetails(Map* map);
   void RecordScriptDetails(Script* obj);
   void RecordTemplateInfoDetails(TemplateInfo* obj);
   void RecordSharedFunctionInfoDetails(SharedFunctionInfo* sfi);
 
   bool RecordFixedArrayHelper(HeapObject* parent, FixedArray* array,
                               int subtype, size_t overhead);
   void RecursivelyRecordFixedArrayHelper(HeapObject* parent, FixedArray* array,
                                          int subtype);
   template <class HashTable>
   void RecordHashTableHelper(HeapObject* parent, HashTable* array, int subtype);
   Heap* heap_;
   ObjectStats* stats_;
 
   friend class ObjectStatsCollector::CompilationCacheTableVisitor;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_OBJECT_STATS_H_