Make CFX_WideString::FromLocal() take a CFX_ByteStringC arg

It doesn't persist the string beyond the duration of the
call, hence it should take the *StringC variant. Doing so
avoids some allocs by changing to the *StringC ctor in a few
places, at the cost of some explicit .ToByteStringC() calls
(which are cheap).

Review URL: https://codereview.chromium.org/1862953004

1 files changed, 9 insertions, 5 deletions

diff --git a/core/fpdfdoc/doc_basic.cpp b/core/fpdfdoc/doc_basic.cpp
index 9318387f7f..308bf04287 100644
--- a/core/fpdfdoc/doc_basic.cpp
+++ b/core/fpdfdoc/doc_basic.cpp
@@ -315,23 +315,27 @@ 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->GetStringBy("F"));
+      *csFileName = CFX_WideString::FromLocal(pDict->GetConstStringBy("F"));
     }
     if (pDict->GetStringBy("FS") == "URL")
       return true;
     if (csFileName->IsEmpty()) {
       if (pDict->KeyExist("DOS")) {
-        *csFileName = CFX_WideString::FromLocal(pDict->GetStringBy("DOS"));
+        *csFileName = CFX_WideString::FromLocal(
+            pDict->GetStringBy("DOS").AsByteStringC());
       } else if (pDict->KeyExist("Mac")) {
-        *csFileName = CFX_WideString::FromLocal(pDict->GetStringBy("Mac"));
+        *csFileName = CFX_WideString::FromLocal(
+            pDict->GetStringBy("Mac").AsByteStringC());
       } else if (pDict->KeyExist("Unix")) {
-        *csFileName = CFX_WideString::FromLocal(pDict->GetStringBy("Unix"));
+        *csFileName = CFX_WideString::FromLocal(
+            pDict->GetStringBy("Unix").AsByteStringC());
       } else {
         return false;
       }
     }
   } else if (m_pObj->IsString()) {
-    *csFileName = CFX_WideString::FromLocal(m_pObj->GetString());
+    *csFileName =
+        CFX_WideString::FromLocal(m_pObj->GetString().AsByteStringC());
   } else {
     return false;
   }