Use EmbedderHeapTracer instead of object grouping when trace_embedder_heap flag is set

src/heap/heap.h

 // Copyright 2012 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_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 894 matching lines @@
         return lo_space();
       default:
         return paged_space(idx);
     }
   }
 
   // Returns name of the space.
   const char* GetSpaceName(int idx);
 
   // ===========================================================================
-  // API. ======================================================================
+  // Embedder heap tracing. ====================================================
   // ===========================================================================
 
   void SetEmbedderHeapTracer(EmbedderHeapTracer* tracer);
 
+  EmbedderHeapTracer* embedder_heap_tracer() { return embedder_heap_tracer_; }
+
+  bool UsingEmbedderHeapTracer() {
+    return FLAG_trace_embedder_heap && embedder_heap_tracer_;
+  }
+
+  void TracePossibleWrapper(JSObject* js_object);
+
   void RegisterExternallyReferencedObject(Object** object);
 
   // ===========================================================================
   // Getters to other components. ==============================================
   // ===========================================================================
 
   GCTracer* tracer() { return tracer_; }
 
   MemoryAllocator* memory_allocator() { return memory_allocator_; }
 
-  EmbedderHeapTracer* embedder_heap_tracer() { return embedder_heap_tracer_; }
-
   PromotionQueue* promotion_queue() { return &promotion_queue_; }
 
   inline Isolate* isolate();
 
   MarkCompactCollector* mark_compact_collector() {
     return mark_compact_collector_;
   }
 
   // ===========================================================================
   // Root set access. ==========================================================
@@ skipping 1719 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_