Heap profiler: reduce heap snapshots size.

src/list-inl.h

Index: src/list-inl.h
diff --git a/src/list-inl.h b/src/list-inl.h
index e41db11fc5430d1120cc13c823d71f46f84706ce..e277bc87234434480bd49430b3ce70756f612199 100644
--- a/src/list-inl.h
+++ b/src/list-inl.h
@@ -127,6 +127,13 @@ void List<T, P>::Iterate(void (*callback)(T* x)) {
 
 
 template<typename T, class P>
+template<class Visitor>
+void List<T, P>::Iterate(Visitor* visitor) {
+  for (int i = 0; i < length_; i++) visitor->Apply(&data_[i]);
+}
+
+
+template<typename T, class P>
 bool List<T, P>::Contains(const T& elm) {
   for (int i = 0; i < length_; i++) {
     if (data_[i] == elm)