Handle StepIn for constructors through PrepareStep just like for regular calls

src/runtime/runtime-classes.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <stdlib.h>
 #include <limits>
 
 #include "src/arguments.h"
@@ skipping 464 matching lines @@
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, home_object, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 2);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 3);
 
   return StoreKeyedToSuper(isolate, home_object, receiver, key, value, SLOPPY);
 }
 
 
-RUNTIME_FUNCTION(Runtime_HandleStepInForDerivedConstructors) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 1);
-  CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
-  Debug* debug = isolate->debug();
-  // Handle stepping into constructors if step into is active.
-  if (debug->StepInActive()) debug->HandleStepIn(function, true);
-  return *isolate->factory()->undefined_value();
-}
-
-
 RUNTIME_FUNCTION(Runtime_DefaultConstructorCallSuper) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, new_target, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, super_constructor, 1);
   JavaScriptFrameIterator it(isolate);
 
   // Determine the actual arguments passed to the function.
   int argument_count = 0;
   base::SmartArrayPointer<Handle<Object>> arguments =
       Runtime::GetCallerArguments(isolate, 0, &argument_count);
 
   Handle<Object> result;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, result, Execution::New(isolate, super_constructor, new_target,
                                       argument_count, arguments.get()));
 
   return *result;
 }
 
 }  // namespace internal
 }  // namespace v8