[debugger] simplify debug stepping.

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index 7aa7013c0db771aae9c8236a19621d03cb98240e..37055044db9d5f6d2f4dce87dc7443a995756228 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -840,11 +840,12 @@ 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());
-  __ li(t1, Operand(step_in_enabled));
+  ExternalReference last_step_action =
+      ExternalReference::debug_last_step_action_address(masm->isolate());
+  STATIC_ASSERT(StepFrame > StepIn);
+  __ li(t1, Operand(last_step_action));
   __ lb(t1, MemOperand(t1));
-  __ Branch(&prepare_step_in_if_stepping, ne, t1, Operand(zero_reg));
+  __ Branch(&prepare_step_in_if_stepping, ge, t1, Operand(StepIn));
 
   // Flood function if we need to continue stepping in the suspended generator.
   ExternalReference debug_suspended_generator =