Remove some c_str() calls from StringCs in xfa docs.

xfa/fxfa/app/xfa_ffdocview.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 "xfa/fxfa/include/xfa_ffdocview.h"
 
 #include "core/fxcrt/include/fx_ext.h"
 #include "xfa/fxfa/app/xfa_ffbarcode.h"
@@ skipping 144 matching lines @@
       CFX_WideString wsLimit;
       pAppProvider->LoadString(XFA_IDS_ValidateLimit, wsLimit);
       if (!wsLimit.IsEmpty()) {
         CFX_WideString wsTemp;
         wsTemp.Format(wsLimit.c_str(), iRemain);
         wsMsg += FX_WSTRC(L"\n") + wsTemp;
       }
     }
     CFX_WideString wsTitle;
     pAppProvider->LoadString(XFA_IDS_AppName, wsTitle);
-    pAppProvider->MsgBox(wsMsg.AsStringC(), wsTitle.AsStringC(),
-                         XFA_MBICON_Status, XFA_MB_OK);
+    pAppProvider->MsgBox(wsMsg, wsTitle, XFA_MBICON_Status, XFA_MB_OK);
   }
   m_arrNullTestMsg.RemoveAll();
 }
 void CXFA_FFDocView::UpdateDocView() {
   if (IsUpdateLocked()) {
     return;
   }
   LockUpdate();
   int32_t iNewAdds = m_NewAddedNodes.GetSize();
   for (int32_t i = 0; i < iNewAdds; i++) {
@@ skipping 722 matching lines @@
 CXFA_WidgetAcc* CXFA_WidgetAccIterator::GetCurrentWidgetAcc() {
   return NULL;
 }
 FX_BOOL CXFA_WidgetAccIterator::SetCurrentWidgetAcc(CXFA_WidgetAcc* hWidget) {
   return FALSE;
 }
 void CXFA_WidgetAccIterator::SkipTree() {
   m_ContentIterator.SkipChildrenAndMoveToNext();
   m_pCurWidgetAcc = NULL;
 }