971   JavaScriptFrameIterator frames_it(isolate_, frame_id);  in PrepareStep()  local
972   JavaScriptFrame* frame = frames_it.frame();  in PrepareStep()
984     frames_it.Advance();  in PrepareStep()
986     JSFunction* function = frames_it.frame()->function();  in PrepareStep()
1020       frames_it.Advance();  in PrepareStep()
1022       while (!frames_it.done() &&  in PrepareStep()
1023              !frames_it.frame()->function()->shared()->IsSubjectToDebugging()) {  in PrepareStep()
1026         Deoptimizer::DeoptimizeFunction(frames_it.frame()->function());  in PrepareStep()
1027         frames_it.Advance();  in PrepareStep()
1029       if (!frames_it.done()) {  in PrepareStep()
1031         Handle<JSFunction> caller_function(frames_it.frame()->function());  in PrepareStep()
1033         thread_local_.target_fp_ = frames_it.frame()->UnpaddedFP();  in PrepareStep()