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

fpdfsdk/fpdfxfa/include/fpdfxfa_app.h

 // 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
 
 #ifndef FPDFSDK_FPDFXFA_INCLUDE_FPDFXFA_APP_H_
 #define FPDFSDK_FPDFXFA_INCLUDE_FPDFXFA_APP_H_
 
 #include "xfa/fxfa/include/fxfa.h"
@@ skipping 33 matching lines @@
   void GetFoxitVersion(CFX_WideString& wsFoxitVersion) override {
     wsFoxitVersion = L"7.0";
   }
 
   void GetAppName(CFX_WideString& wsName) override;
   void GetFoxitAppName(CFX_WideString& wsFoxitName) override {
     wsFoxitName = L"Foxit";
   }
 
   void Beep(uint32_t dwType) override;
-  int32_t MsgBox(const CFX_WideStringC& wsMessage,
-                 const CFX_WideStringC& wsTitle,
+  int32_t MsgBox(const CFX_WideString& wsMessage,
+                 const CFX_WideString& wsTitle,
                  uint32_t dwIconType,
                  uint32_t dwButtonType) override;
-  void Response(CFX_WideString& wsAnswer,
-                const CFX_WideStringC& wsQuestion,
-                const CFX_WideStringC& wsTitle,
-                const CFX_WideStringC& wsDefaultAnswer,
-                FX_BOOL bMark) override;
+  CFX_WideString Response(const CFX_WideString& wsQuestion,
+                          const CFX_WideString& wsTitle,
+                          const CFX_WideString& wsDefaultAnswer,
+                          FX_BOOL bMark) override;
 
   int32_t GetDocumentCountInBatch() override;
   int32_t GetCurDocumentInBatch() override;
 
-  IFX_FileRead* DownloadURL(const CFX_WideStringC& wsURL) override;
-  FX_BOOL PostRequestURL(const CFX_WideStringC& wsURL,
-                         const CFX_WideStringC& wsData,
-                         const CFX_WideStringC& wsContentType,
-                         const CFX_WideStringC& wsEncode,
-                         const CFX_WideStringC& wsHeader,
+  IFX_FileRead* DownloadURL(const CFX_WideString& wsURL) override;
+  FX_BOOL PostRequestURL(const CFX_WideString& wsURL,
+                         const CFX_WideString& wsData,
+                         const CFX_WideString& wsContentType,
+                         const CFX_WideString& wsEncode,
+                         const CFX_WideString& wsHeader,
                          CFX_WideString& wsResponse) override;
-  FX_BOOL PutRequestURL(const CFX_WideStringC& wsURL,
-                        const CFX_WideStringC& wsData,
-                        const CFX_WideStringC& wsEncode) override;
+  FX_BOOL PutRequestURL(const CFX_WideString& wsURL,
+                        const CFX_WideString& wsData,
+                        const CFX_WideString& wsEncode) override;
 
   void LoadString(int32_t iStringID, CFX_WideString& wsString) override;
   IFWL_AdapterTimerMgr* GetTimerMgr() override;
 
   CFX_ArrayTemplate<CPDFDoc_Environment*> m_pEnvList;
 
  protected:
   static CPDFXFA_App* g_pApp;
 
   FX_BOOL m_bJavaScriptInitialized;
   CXFA_FFApp* m_pXFAApp;
   FXJSE_HRUNTIME m_hJSERuntime;
   IFXJS_Runtime* m_pJSRuntime;
   CFX_WideString m_csAppType;
   bool m_bOwnedRuntime;
 };
 
 #endif  // FPDFSDK_FPDFXFA_INCLUDE_FPDFXFA_APP_H_