New GC related APIs: Implicit references.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index b3b23b579cd77e4d67a92044a48e8d1b3d86db5a..43761f547ec0908402fd99da3a52e04a335e899a 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -5913,6 +5913,17 @@ void V8::SetRetainedObjectInfo(Isolate* exported_isolate,
 }
 
 
+void V8::SetObjectGroupRepresentativeObject(
+      Isolate* exported_isolate,
+      UniqueId id,
+      const Persistent<Object>& object) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(exported_isolate);
+  isolate->global_handles()->SetRepresentativeObject(
+      id,
+      i::Handle<i::HeapObject>::cast(Utils::OpenHandle(*object)).location());
+}
+
+
 void V8::AddImplicitReferences(Persistent<Object> parent,
                                Persistent<Value>* children,
                                size_t length) {
@@ -5925,6 +5936,15 @@ void V8::AddImplicitReferences(Persistent<Object> parent,
 }
 
 
+void V8::AddImplicitReference(Isolate* exported_isolate,
+                              UniqueId id,
+                              const Persistent<Value>& object) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(exported_isolate);
+  isolate->global_handles()
+      ->AddImplicitReference(id, reinterpret_cast<i::Object**>(*object));
+}
+
+
 intptr_t Isolate::AdjustAmountOfExternalAllocatedMemory(
     intptr_t change_in_bytes) {
   i::Heap* heap = reinterpret_cast<i::Isolate*>(this)->heap();