[debugger] tuned StepNext and StepOut at return position

src/debug/debug.h

 // Copyright 2012 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.
 
 #ifndef V8_DEBUG_DEBUG_H_
 #define V8_DEBUG_DEBUG_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/base/atomicops.h"
@@ skipping 544 matching lines @@
 
     // Counter for generating next break id.
     int break_count_;
 
     // Current break id.
     int break_id_;
 
     // Frame id for the frame of the current break.
     StackFrame::Id break_frame_id_;
 
+    StackFrame::Id last_step_frame_id_;
+
     // Step action for last step performed.
     StepAction last_step_action_;
 
     // Source statement position from last step next action.
     int last_statement_position_;
 
     // Frame pointer from last step next or step frame action.
     int last_frame_count_;
 
     // Frame pointer of the target frame we want to arrive at.
@@ skipping 224 matching lines @@
                                   Handle<Code> code);
   static bool DebugBreakSlotIsPatched(Address pc);
   static void ClearDebugBreakSlot(Isolate* isolate, Address pc);
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_DEBUG_DEBUG_H_