Introduce EmbedderHeapTracer

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index f933540ba3b1698528c7fee65b3aaa6941c6057c..75218d29a38f2ab30736bb36a28c4d44fc7556f1 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -7170,6 +7170,15 @@ void V8::AddGCEpilogueCallback(GCCallback callback, GCType gc_type) {
       reinterpret_cast<v8::Isolate::GCCallback>(callback), gc_type, false);
 }
 
+void Isolate::SetEmbedderHeapTracer(EmbedderHeapTracer* tracer) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
+  isolate->heap()->SetEmbedderHeapTracer(tracer);
+}
+
+void Isolate::UnsetEmbedderHeapTracer() {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
+  isolate->heap()->UnsetEmbedderHeapTracer();
+}
 
 void Isolate::AddMemoryAllocationCallback(MemoryAllocationCallback callback,
                                           ObjectSpace space,