[heap] Integrate embedder heap tracer into incremental marking

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index b2c637bc6361aef2cdecde137d276baa1eb6f5ed..6772900cf81214219213d0b5d84c32d8add1ef17 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -490,6 +490,8 @@ class MarkCompactCollector {
 
   Sweeper& sweeper() { return sweeper_; }
 
+  bool RequiresImmediateWrapperProcessing();
+
   void RegisterWrappersWithEmbedderHeapTracer();
 
   void SetEmbedderHeapTracer(EmbedderHeapTracer* tracer);
@@ -500,6 +502,8 @@ class MarkCompactCollector {
 
   void TracePossibleWrapper(JSObject* js_object);
 
+  size_t wrappers_to_trace() { return wrappers_to_trace_.size(); }
+
  private:
   class EvacuateNewSpacePageVisitor;
   class EvacuateNewSpaceVisitor;