[debugger] simplify debug stepping.

src/x87/builtins-x87.cc

Index: src/x87/builtins-x87.cc
diff --git a/src/x87/builtins-x87.cc b/src/x87/builtins-x87.cc
index 0f93537ebdf92563bdb4d385bf325e6c260d0fe0..5789c2c2807286c5a418a7f6ce28d96449d05a78 100644
--- a/src/x87/builtins-x87.cc
+++ b/src/x87/builtins-x87.cc
@@ -410,10 +410,11 @@ void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
   // Flood function if we are stepping.
   Label prepare_step_in_if_stepping, prepare_step_in_suspended_generator;
   Label stepping_prepared;
-  ExternalReference step_in_enabled =
-      ExternalReference::debug_step_in_enabled_address(masm->isolate());
-  __ cmpb(Operand::StaticVariable(step_in_enabled), Immediate(0));
-  __ j(not_equal, &prepare_step_in_if_stepping);
+  ExternalReference last_step_action =
+      ExternalReference::debug_last_step_action_address(masm->isolate());
+  STATIC_ASSERT(StepFrame > StepIn);
+  __ cmpb(Operand::StaticVariable(last_step_action), Immediate(StepIn));
+  __ j(greater_equal, &prepare_step_in_if_stepping);
 
   // Flood function if we need to continue stepping in the suspended generator.
   ExternalReference debug_suspended_generator =