Report initial_map field of JSFunction in heap snapshot.

R=verwaest@chromium.org, yurys@chromium.org

Review URL: https://codereview.chromium.org/19256020

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15711 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap-snapshot-generator.cc

@@ -997,6 +997,9 @@ void V8HeapExplorer::ExtractJSObjectReferences(
         SetPropertyReference(
             obj, entry,
             heap_->prototype_string(), js_fun->prototype());
+        SetInternalReference(
+            obj, entry, "initial_map", proto_or_map,
+            JSFunction::kPrototypeOrInitialMapOffset);
       }
     }
     SharedFunctionInfo* shared_info = js_fun->shared();