[debugger] tuned StepNext and StepOut at return position

src/runtime/runtime-debug.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 "src/arguments.h"
 #include "src/compiler.h"
 #include "src/debug/debug-coverage.h"
 #include "src/debug/debug-evaluate.h"
@@ skipping 1790 matching lines @@
 
   return *str;
 }
 
 // On function call, depending on circumstances, prepare for stepping in,
 // or perform a side effect check.
 RUNTIME_FUNCTION(Runtime_DebugOnFunctionCall) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, fun, 0);
-  if (isolate->debug()->last_step_action() >= StepIn) {
+  if (isolate->debug()->last_step_action() != StepNone) {
     isolate->debug()->PrepareStepIn(fun);
   }
   if (isolate->needs_side_effect_check() &&
       !isolate->debug()->PerformSideEffectCheck(fun)) {
     return isolate->heap()->exception();
   }
   return isolate->heap()->undefined_value();
 }
 
 // Set one shot breakpoints for the suspended generator object.
@@ skipping 122 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_DebugTogglePreciseCoverage) {
   SealHandleScope shs(isolate);
   CONVERT_BOOLEAN_ARG_CHECKED(enable, 0);
   Coverage::TogglePrecise(isolate, enable);
   return isolate->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8