[debugger] introduce abstract interface for break location.

src/interpreter/source-position-table.cc

 // Copyright 2016 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.
 
 #include "src/interpreter/source-position-table.h"
 
 #include "src/assembler.h"
 #include "src/objects-inl.h"
 #include "src/objects.h"
 
@@ skipping 59 matching lines @@
     DCHECK(bytecode_offset_ < new_bytecode_offset || index_ == 0);
     bytecode_offset_ = new_bytecode_offset;
     uint32_t source_position_and_type =
         static_cast<uint32_t>(Smi::cast(table_->get(index_ + 1))->value());
     is_statement_ = IsStatementField::decode(source_position_and_type);
     source_position_ = SourcePositionField::decode(source_position_and_type);
   }
   index_ += 2;
 }
 
-int SourcePositionTableIterator::PositionFromBytecodeOffset(
-    BytecodeArray* bytecode_array, int bytecode_offset) {
-  int last_position = 0;
-  for (SourcePositionTableIterator iterator(bytecode_array);
-       !iterator.done() && iterator.bytecode_offset() <= bytecode_offset;
-       iterator.Advance()) {
-    last_position = iterator.source_position();
-  }
-  return last_position;
-}
-
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8