Reland of "[heap] Report wrappers after processing the marking deque incrementally"

src/heap/heap.cc

 // 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.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/context-slot-cache.h"
 #include "src/base/bits.h"
@@ skipping 1592 matching lines @@
   SetGCState(SCAVENGE);
 
   // Implements Cheney's copying algorithm
   LOG(isolate_, ResourceEvent("scavenge", "begin"));
 
   // Used for updating survived_since_last_expansion_ at function end.
   size_t survived_watermark = PromotedSpaceSizeOfObjects();
 
   scavenge_collector_->SelectScavengingVisitorsTable();
 
-  local_embedder_heap_tracer()->RegisterWrappersWithRemoteTracer();
-
   // Flip the semispaces.  After flipping, to space is empty, from space has
   // live objects.
   new_space_->Flip();
   new_space_->ResetAllocationInfo();
 
   // We need to sweep newly copied objects which can be either in the
   // to space or promoted to the old generation.  For to-space
   // objects, we treat the bottom of the to space as a queue.  Newly
   // copied and unswept objects lie between a 'front' mark and the
   // allocation pointer.
@@ skipping 87 matching lines @@
   // Set age mark.
   new_space_->set_age_mark(new_space_->top());
 
   ArrayBufferTracker::FreeDeadInNewSpace(this);
 
   // Update how much has survived scavenge.
   DCHECK_GE(PromotedSpaceSizeOfObjects(), survived_watermark);
   IncrementYoungSurvivorsCounter(PromotedSpaceSizeOfObjects() +
                                  new_space_->Size() - survived_watermark);
 
+  // Scavenger may find new wrappers by iterating objects promoted onto a black
+  // page.
+  local_embedder_heap_tracer()->RegisterWrappersWithRemoteTracer();
+
   LOG(isolate_, ResourceEvent("scavenge", "end"));
 
   SetGCState(NOT_IN_GC);
 }
 
 
 String* Heap::UpdateNewSpaceReferenceInExternalStringTableEntry(Heap* heap,
                                                                 Object** p) {
   MapWord first_word = HeapObject::cast(*p)->map_word();
 
@@ skipping 4770 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8