[debugger] use source position to identify break points.

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 57 matching lines @@
   // the address.
   static BreakLocation FromCodeOffset(Handle<DebugInfo> debug_info, int offset);
 
   static BreakLocation FromFrame(Handle<DebugInfo> debug_info,
                                  JavaScriptFrame* frame);
 
   static void AllForStatementPosition(Handle<DebugInfo> debug_info,
                                       int statement_position,
                                       List<BreakLocation>* result_out);
 
+  // Find break location (for a break point) from source positon.
   static BreakLocation FromPosition(Handle<DebugInfo> debug_info, int position,
                                     BreakPositionAlignment alignment);
 
   bool IsDebugBreak() const;
 
   inline bool IsReturn() const { return type_ == DEBUG_BREAK_SLOT_AT_RETURN; }
   inline bool IsCall() const { return type_ == DEBUG_BREAK_SLOT_AT_CALL; }
   inline bool IsTailCall() const {
     return type_ == DEBUG_BREAK_SLOT_AT_TAIL_CALL;
   }
   inline bool IsDebugBreakSlot() const { return type_ >= DEBUG_BREAK_SLOT; }
   inline bool IsDebuggerStatement() const {
     return type_ == DEBUGGER_STATEMENT;
   }
-  inline bool HasBreakPoint() const {
-    return debug_info_->HasBreakPoint(code_offset_);
-  }
+
+  bool HasBreakPoint() const;
 
   Handle<Object> BreakPointObjects() const;
 
   void SetBreakPoint(Handle<Object> break_point_object);
   void ClearBreakPoint(Handle<Object> break_point_object);
 
   void SetOneShot();
   void ClearOneShot();
 
   inline int position() const { return position_; }
@@ skipping 706 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_