Introduce api for incremental wrapper tracing

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 5c724bf3ee8d48f6fde9fcc0f194df4d564e469c..ab4e72655c47e79d7660c14c5e1bdb619c4c2715 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -1626,6 +1626,13 @@ void Heap::Scavenge() {
 
   scavenge_collector_->SelectScavengingVisitorsTable();
 
+  if (UsingEmbedderHeapTracer()) {
+    // Register found wrappers with embedder so he can add them to his marking
+    // deque and correctly manage the case when v8 scavenger collects the
+    // wrappers by either keeping wrappables alive, or cleaning marking deque.
+    mark_compact_collector()->RegisterWrappersWithEmbedderHeapTracer();
+  }
+
   array_buffer_tracker()->PrepareDiscoveryInNewSpace();
 
   // Flip the semispaces.  After flipping, to space is empty, from space has