[debugger] use absolute source positions for break locations.

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 160 matching lines @@
           debug_info_->abstract_code()->GetCode()->instruction_start());
     }
 
    private:
     int GetModeMask(BreakLocatorType type);
     RelocInfo::Mode rmode() { return reloc_iterator_.rinfo()->rmode(); }
     RelocInfo* rinfo() { return reloc_iterator_.rinfo(); }
 
     RelocIterator reloc_iterator_;
     SourcePositionTableIterator source_position_iterator_;
-    int start_position_;
     DISALLOW_COPY_AND_ASSIGN(CodeIterator);
   };
 
   class BytecodeArrayIterator : public Iterator {
    public:
     BytecodeArrayIterator(Handle<DebugInfo> debug_info, BreakLocatorType type);
     ~BytecodeArrayIterator() override {}
 
     BreakLocation GetBreakLocation() override;
     bool Done() const override { return source_position_iterator_.done(); }
     void Next() override;
 
     int code_offset() override {
       return source_position_iterator_.code_offset();
     }
 
    private:
     DebugBreakType GetDebugBreakType();
 
     SourcePositionTableIterator source_position_iterator_;
     BreakLocatorType break_locator_type_;
-    int start_position_;
     DISALLOW_COPY_AND_ASSIGN(BytecodeArrayIterator);
   };
 
   static Iterator* GetIterator(Handle<DebugInfo> debug_info,
                                BreakLocatorType type = ALL_BREAK_LOCATIONS);
 
  private:
   friend class Debug;
 
   static int BreakIndexFromCodeOffset(Handle<DebugInfo> debug_info, int offset);
@@ skipping 599 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_