Debugger: PreservePositionScope should clear positions inside the scope.

src/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_H_
 #define V8_DEBUG_H_
 
 #include "src/allocation.h"
 #include "src/arguments.h"
 #include "src/assembler.h"
@@ skipping 168 matching lines @@
     bool RinfoDone() const;
     void RinfoNext();
 
     Handle<DebugInfo> debug_info_;
     BreakLocatorType type_;
     RelocIterator reloc_iterator_;
     RelocIterator reloc_iterator_original_;
     int break_index_;
     int position_;
     int statement_position_;
+    bool has_immediate_position_;
 
     DisallowHeapAllocation no_gc_;
 
     DISALLOW_COPY_AND_ASSIGN(Iterator);
   };
 
   friend class Debug;
 
   static int BreakIndexFromAddress(Handle<DebugInfo> debug_info,
                                    BreakLocatorType type, Address pc);
@@ skipping 631 matching lines @@
   // several frames above.
   // There is no calling conventions here, because it never actually gets
   // called, it only gets returned to.
   static void GenerateFrameDropperLiveEdit(MacroAssembler* masm);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEBUG_H_