XFA: merge patch from CL 733693003, getting rid of more casts

core/include/fxcrt/fx_string.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 _FX_STRING_H_
 #define _FX_STRING_H_
 class CFX_ByteStringC;
 class CFX_ByteString;
@@ skipping 622 matching lines @@
     ~CFX_WideString();
 
     static CFX_WideString       FromLocal(const char* str, FX_STRSIZE len = -1);
 
     static CFX_WideString       FromUTF8(const char* str, FX_STRSIZE len);
 
     static CFX_WideString       FromUTF16LE(const unsigned short* str, FX_STRSIZE len);
 
     static FX_STRSIZE       WStringLength(const unsigned short* str);
 
+    // Explicit conversion to raw string
+    FX_LPCWSTR c_str() const
+    {
+        return m_pData ? m_pData->m_String : L"";
+    }
+
+    // Implicit conversion to C-style wide string -- deprecated
     operator FX_LPCWSTR() const
     {
-        return m_pData ? m_pData->m_String : (FX_WCHAR*)L"";
+        return m_pData ? m_pData->m_String : L"";
     }
 
     void                                        Empty();
 
 
     FX_BOOL                                     IsEmpty() const
     {
         return !GetLength();
     }
 
@@ skipping 99 matching lines @@
     CFX_StringDataW*            m_pData;
     void                                        CopyBeforeWrite();
     void                                        AllocBeforeWrite(FX_STRSIZE nLen);
     void                                        ConcatInPlace(FX_STRSIZE nSrcLen, FX_LPCWSTR lpszSrcData);
     void                                        ConcatCopy(FX_STRSIZE nSrc1Len, FX_LPCWSTR lpszSrc1Data, FX_STRSIZE nSrc2Len, FX_LPCWSTR lpszSrc2Data);
     void                                        AssignCopy(FX_STRSIZE nSrcLen, FX_LPCWSTR lpszSrcData);
     void                                        AllocCopy(CFX_WideString& dest, FX_STRSIZE nCopyLen, FX_STRSIZE nCopyIndex) const;
 };
 inline CFX_WideStringC::CFX_WideStringC(const CFX_WideString& src)
 {
-    m_Ptr = (FX_LPCWSTR)src;
+    m_Ptr = src.c_str();
     m_Length = src.GetLength();
 }
 inline CFX_WideStringC& CFX_WideStringC::operator = (const CFX_WideString& src)
 {
-    m_Ptr = (FX_LPCWSTR)src;
+    m_Ptr = src.c_str();
     m_Length = src.GetLength();
     return *this;
 }
 
 inline CFX_WideString operator + (const CFX_WideStringC& str1, const CFX_WideStringC& str2)
 {
     return CFX_WideString(str1, str2);
 }
 inline CFX_WideString operator + (const CFX_WideStringC& str1, FX_LPCWSTR str2)
 {
@@ skipping 53 matching lines @@
 FX_FLOAT FX_atof(FX_BSTR str);
 void FX_atonum(FX_BSTR str, FX_BOOL& bInteger, void* pData);
 FX_STRSIZE FX_ftoa(FX_FLOAT f, FX_LPSTR buf);
 CFX_ByteString  FX_UTF8Encode(FX_LPCWSTR pwsStr, FX_STRSIZE len);
 inline CFX_ByteString   FX_UTF8Encode(FX_WSTR wsStr)
 {
     return FX_UTF8Encode(wsStr.GetPtr(), wsStr.GetLength());
 }
 inline CFX_ByteString   FX_UTF8Encode(const CFX_WideString &wsStr)
 {
-    return FX_UTF8Encode((FX_LPCWSTR)wsStr, wsStr.GetLength());
+    return FX_UTF8Encode(wsStr.c_str(), wsStr.GetLength());
 }
 #endif