Heap profiler: consider Function instances separately, similar to Arrays and Objects.

src/heap-profiler.cc

Index: src/heap-profiler.cc
diff --git a/src/heap-profiler.cc b/src/heap-profiler.cc
index 5e945b49a0ca126c72eaba27ccaa746d00039d8b..c1122c4b79b62a72047394c661e1fdbe66149d89 100644
--- a/src/heap-profiler.cc
+++ b/src/heap-profiler.cc
@@ -67,9 +67,10 @@ JSObjectsCluster Clusterizer::Clusterize(HeapObject* obj, bool fine_grain) {
   if (obj->IsJSObject()) {
     JSObject* js_obj = JSObject::cast(obj);
     String* constructor = JSObject::cast(js_obj)->constructor_name();
-    // Differentiate Object and Array instances.
+    // Differentiate Array, Function, and Object instances.
     if (fine_grain && (constructor == Heap::Object_symbol() ||
-                       constructor == Heap::Array_symbol())) {
+                       constructor == Heap::Array_symbol() ||
+                       constructor == Heap::function_class_symbol())) {
       return JSObjectsCluster(constructor, obj);
     } else {
       return JSObjectsCluster(constructor);