Make down-conversion explicit from CFX_ByteString to CFX_ByteStringC.

core/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/fpdf_page/pageint.h"
 
 #include <limits.h>
 
@@ skipping 409 matching lines @@
         return nullptr;
       }
       CFX_ByteString key =
           PDF_NameDecode(CFX_ByteStringC(m_WordBuffer + 1, m_WordSize - 1));
       CPDF_Object* pObj = ReadNextObject(TRUE);
       if (!pObj) {
         pDict->Release();
         return nullptr;
       }
       if (!key.IsEmpty()) {
-        pDict->SetAt(key, pObj);
+        pDict->SetAt(key.AsByteStringC(), pObj);
       } else {
         pObj->Release();
       }
     }
     return pDict;
   }
   if (first_char == '[') {
     if (!bAllowNestedArray && bInArray) {
       return NULL;
     }
@@ skipping 444 matching lines @@
       }
       m_Status = Done;
       return;
     }
     steps++;
     if (pPause && pPause->NeedToPauseNow()) {
       break;
     }
   }
 }