remove undetectable strings

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 7e85e59bdb169ea56e6fc862d7d21d01cd2defbe..80f4d4dba21daddf17c25573dec397767955e228 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9169,23 +9169,6 @@ bool String::SlowEquals(Handle<String> one, Handle<String> two) {
 }
 
 
-bool String::MarkAsUndetectable() {
-  if (StringShape(this).IsInternalized()) return false;
-
-  Map* map = this->map();
-  Heap* heap = GetHeap();
-  if (map == heap->string_map()) {
-    this->set_map(heap->undetectable_string_map());
-    return true;
-  } else if (map == heap->one_byte_string_map()) {
-    this->set_map(heap->undetectable_one_byte_string_map());
-    return true;
-  }
-  // Rest cannot be marked as undetectable
-  return false;
-}
-
-
 bool String::IsUtf8EqualTo(Vector<const char> str, bool allow_prefix_match) {
   int slen = length();
   // Can't check exact length equality, but we can check bounds.