Cleanup native, collected, and stub code handling in profiler

runtime/vm/stack_frame.cc

Index: runtime/vm/stack_frame.cc
diff --git a/runtime/vm/stack_frame.cc b/runtime/vm/stack_frame.cc
index 7c1e5e74f2b643dfa3423a60217d2cdfcdded829..ad58fb4464f0e9e594cdf5aa2682be3380ef2dd9 100644
--- a/runtime/vm/stack_frame.cc
+++ b/runtime/vm/stack_frame.cc
@@ -150,7 +150,7 @@ RawCode* StackFrame::LookupDartCode() const {
   // that the code is called while a GC is in progress, that is ok.
   NoGCScope no_gc;
   RawCode* code = GetCodeObject();
-  ASSERT(code == Code::null() || code->ptr()->function_ != Function::null());
+  ASSERT(code == Code::null() || code->ptr()->owner_ != Function::null());
   return code;
 }