[debugger] simplify step over recursive function call.

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/arguments.h"
 #include "src/assembler.h"
@@ skipping 612 matching lines @@
 
     // Source statement position from last step next action.
     int last_statement_position_;
 
     // Number of steps left to perform before debug event.
     int step_count_;
 
     // Frame pointer from last step next or step frame action.
     Address last_fp_;
 
-    // Number of queued steps left to perform before debug event.
-    int queued_step_count_;
-
     // Frame pointer for the frame where debugger should be called when current
     // step out action is completed.
     Address step_out_fp_;
 
     // Whether functions are flooded on entry for step-in and step-frame.
     // If we stepped out to the embedder, disable flooding to spill stepping
     // to the next call that the embedder makes.
     bool step_in_enabled_;
 
     // Stores the way how LiveEdit has patched the stack. It is used when
@@ skipping 107 matching lines @@
   static void PatchDebugBreakSlot(Isolate* isolate, Address pc,
                                   Handle<Code> code);
   static void ClearDebugBreakSlot(Isolate* isolate, Address pc);
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_DEBUG_DEBUG_H_