[debugger] add lcov support to d8.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index dc1ba72f96cc8d4e53db78b043cfd2c8b8f88eb7..c7b92e1b49d3222a24cea27895fa12329db31eac 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6694,8 +6694,10 @@ class Script: public Struct {
   // initializes the line ends array, avoiding expensive recomputations.
   // The non-static version is not allocating and safe for unhandlified
   // callsites.
-  static bool GetPositionInfo(Handle<Script> script, int position,
-                              PositionInfo* info, OffsetFlag offset_flag);
+  V8_EXPORT_PRIVATE static bool GetPositionInfo(Handle<Script> script,
+                                                int position,
+                                                PositionInfo* info,
+                                                OffsetFlag offset_flag);
   bool GetPositionInfo(int position, PositionInfo* info,
                        OffsetFlag offset_flag) const;