Remove CPDF_Object::GetConstString and overrides

core/fpdfdoc/doc_basic.cpp

Index: core/fpdfdoc/doc_basic.cpp
diff --git a/core/fpdfdoc/doc_basic.cpp b/core/fpdfdoc/doc_basic.cpp
index 1cfca7e8eefc1365a0af0c7c93c0d878da90f28b..e0b71df39249158b65f7089ad8fa50da93da6a30 100644
--- a/core/fpdfdoc/doc_basic.cpp
+++ b/core/fpdfdoc/doc_basic.cpp
@@ -316,7 +316,8 @@ bool CPDF_FileSpec::GetFileName(CFX_WideString* csFileName) const {
   if (CPDF_Dictionary* pDict = m_pObj->AsDictionary()) {
     *csFileName = pDict->GetUnicodeTextBy("UF");
     if (csFileName->IsEmpty()) {
-      *csFileName = CFX_WideString::FromLocal(pDict->GetConstStringBy("F"));
+      *csFileName =
+          CFX_WideString::FromLocal(pDict->GetStringBy("F").AsStringC());
     }
     if (pDict->GetStringBy("FS") == "URL")
       return true;