Handle StepIn for constructors through PrepareStep just like for regular calls

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 72 matching lines @@
   inline bool IsReturn() const {
     return RelocInfo::IsDebugBreakSlotAtReturn(rmode_);
   }
   inline bool IsCall() const {
     return RelocInfo::IsDebugBreakSlotAtCall(rmode_);
   }
   inline bool IsConstructCall() const {
     return RelocInfo::IsDebugBreakSlotAtConstructCall(rmode_);
   }
   inline int CallArgumentsCount() const {
-    DCHECK(IsCall());
+    DCHECK(IsStepInLocation());
     return RelocInfo::DebugBreakCallArgumentsCount(data_);
   }
 
   bool IsStepInLocation() const;
   inline bool HasBreakPoint() const {
     return debug_info_->HasBreakPoint(pc_offset_);
   }
 
   Handle<Object> BreakPointObjects() const;
 
@@ skipping 300 matching lines @@
 
   // Stepping handling.
   void PrepareStep(StepAction step_action,
                    int step_count,
                    StackFrame::Id frame_id);
   void ClearStepping();
   void ClearStepOut();
   bool IsStepping() { return thread_local_.step_count_ > 0; }
   bool StepNextContinue(BreakLocation* location, JavaScriptFrame* frame);
   bool StepInActive() { return thread_local_.step_into_fp_ != 0; }
-  void HandleStepIn(Handle<Object> function_obj, bool is_constructor);
+  void HandleStepIn(Handle<Object> function_obj);
   bool StepOutActive() { return thread_local_.step_out_fp_ != 0; }
 
   void GetStepinPositions(JavaScriptFrame* frame, StackFrame::Id frame_id,
                           List<int>* results_out);
 
   bool PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared);
 
   // Returns whether the operation succeeded. Compilation can only be triggered
   // if a valid closure is passed as the second argument, otherwise the shared
   // function needs to be compiled already.
@@ skipping 335 matching lines @@
 
   static void PatchDebugBreakSlot(Address pc, Handle<Code> code);
   static void ClearDebugBreakSlot(Address pc);
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_DEBUG_DEBUG_H_