[debugger] simplify debug stepping.

src/assembler.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 1752 matching lines @@
 }
 
 
 ExternalReference ExternalReference::mod_two_doubles_operation(
     Isolate* isolate) {
   return ExternalReference(Redirect(isolate,
                                     FUNCTION_ADDR(modulo),
                                     BUILTIN_FP_FP_CALL));
 }
 
-
-ExternalReference ExternalReference::debug_step_in_enabled_address(
+ExternalReference ExternalReference::debug_last_step_action_address(
     Isolate* isolate) {
-  return ExternalReference(isolate->debug()->step_in_enabled_address());
+  return ExternalReference(isolate->debug()->last_step_action_address());
 }
 
 ExternalReference ExternalReference::debug_suspended_generator_address(
     Isolate* isolate) {
   return ExternalReference(isolate->debug()->suspended_generator_address());
 }
 
 ExternalReference ExternalReference::fixed_typed_array_base_data_offset() {
   return ExternalReference(reinterpret_cast<void*>(
       FixedTypedArrayBase::kDataOffset - kHeapObjectTag));
@@ skipping 307 matching lines @@
 
 
 void Assembler::DataAlign(int m) {
   DCHECK(m >= 2 && base::bits::IsPowerOfTwo32(m));
   while ((pc_offset() & (m - 1)) != 0) {
     db(0);
   }
 }
 }  // namespace internal
 }  // namespace v8