Stop converting widestring -> c_str -> widestring in several places.

fpdfsdk/pdfwindow/PWL_EditCtrl.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 "fpdfsdk/pdfwindow/PWL_EditCtrl.h"
 
 #include "core/fpdfdoc/include/cpvt_section.h"
 #include "core/fpdfdoc/include/cpvt_word.h"
@@ skipping 446 matching lines @@
     fFontSize = word.fFontSize;
   } else if (HasFlag(PES_RICH)) {
     if (pIterator->GetSection(section)) {
       fFontSize = section.WordProps.fFontSize;
     }
   }
 
   return fFontSize;
 }
 
-void CPWL_EditCtrl::SetText(const FX_WCHAR* csText) {
-  m_pEdit->SetText(csText);
+void CPWL_EditCtrl::SetText(const CFX_WideString& wsText) {
+  m_pEdit->SetText(wsText);
 }
 
 void CPWL_EditCtrl::CopyText() {}
 
 void CPWL_EditCtrl::PasteText() {}
 
 void CPWL_EditCtrl::CutText() {}
 
 void CPWL_EditCtrl::ShowVScrollBar(FX_BOOL bShow) {}
 
-void CPWL_EditCtrl::InsertText(const FX_WCHAR* csText) {
+void CPWL_EditCtrl::InsertText(const CFX_WideString& wsText) {
   if (!IsReadOnly())
-    m_pEdit->InsertText(csText, DEFAULT_CHARSET);
+    m_pEdit->InsertText(wsText, DEFAULT_CHARSET);
 }
 
 void CPWL_EditCtrl::InsertWord(uint16_t word, int32_t nCharset) {
   if (!IsReadOnly())
     m_pEdit->InsertWord(word, nCharset);
 }
 
 void CPWL_EditCtrl::InsertReturn() {
   if (!IsReadOnly())
     m_pEdit->InsertReturn();
@@ skipping 95 matching lines @@
   CPVT_WordPlace wpEnd = m_pEdit->WordIndexToWordPlace(nEndChar);
   return m_pEdit->GetRangeText(CPVT_WordRange(wpStart, wpEnd));
 }
 
 void CPWL_EditCtrl::SetReadyToInput() {
   if (m_bMouseDown) {
     ReleaseCapture();
     m_bMouseDown = FALSE;
   }
 }