Make internalized string parser in JSON.parse GC-safe

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index aa1f94d8145207640f554ece31c9707165f9ad0f..c3ad0dc5a5aafe1c8cfdb7692a7edb24197fa2d3 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -164,8 +164,11 @@ class Factory V8_FINAL {
       uint32_t hash_field);
 
   MUST_USE_RESULT Handle<String> NewOneByteInternalizedString(
-        Vector<const uint8_t> str,
-        uint32_t hash_field);
+      Vector<const uint8_t> str, uint32_t hash_field);
+
+  MUST_USE_RESULT Handle<String> NewOneByteInternalizedSubString(
+      Handle<SeqOneByteString> string, int offset, int length,
+      uint32_t hash_field);
 
   MUST_USE_RESULT Handle<String> NewTwoByteInternalizedString(
         Vector<const uc16> str,