Move map retaining to finalization of incremental marking.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index f1dd4d7efe96b236d1536c0611969bf3c1fa3de4..87bc20ba5e4b74b55826ff35a769181eb3dc5801 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9895,6 +9895,12 @@ Handle<ArrayList> ArrayList::Add(Handle<ArrayList> array, Handle<Object> obj1,
 }
 
 
+bool ArrayList::IsFull() {
+  int capacity = length();
+  return kFirstIndex + Length() == capacity;
+}
+
+
 Handle<ArrayList> ArrayList::EnsureSpace(Handle<ArrayList> array, int length) {
   int capacity = array->length();
   bool empty = (capacity == 0);