Fix offset outside bounds warning on GCC

core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp

Index: core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp
diff --git a/core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp b/core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp
index 89ad5eec33dbc5330e3eb9c02b71f0d6cc07c4bf..294c52443033279eba4453945bfd75adf45b3254 100644
--- a/core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp
@@ -471,7 +471,7 @@ CPDF_Object* CPDF_SyntaxParser::GetObject(CPDF_IndirectObjectHolder* pObjList,
       if (!pObj)
         continue;
 
-      CFX_ByteStringC keyNoSlash(key.c_str() + 1, key.GetLength() - 1);
+      CFX_ByteStringC keyNoSlash(key.raw_str() + 1, key.GetLength() - 1);
       pDict->SetAt(keyNoSlash, pObj);
     }