Fix fx_string.h compile error under chromium checkouts

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_
 
 #include <stdint.h>  // For intptr_t.
@@ skipping 73 matching lines @@
     CFX_ByteStringC& operator = (const CFX_ByteStringC& src)
     {
         m_Ptr = src.m_Ptr;
         m_Length = src.m_Length;
         return *this;
     }
 
     CFX_ByteStringC& operator = (const CFX_ByteString& src);
 
     bool operator== (const char* ptr) const {
-        return strlen(ptr) == m_Length &&
+        return (FX_STRSIZE)FXSYS_strlen(ptr) == m_Length &&
                 FXSYS_memcmp32(ptr, m_Ptr, m_Length) == 0;
     }
     bool operator== (const CFX_ByteStringC& other) const {
         return other.m_Length == m_Length &&
                 FXSYS_memcmp32(other.m_Ptr, m_Ptr, m_Length) == 0;
     }
     bool operator!= (const char* ptr) const { return !(*this == ptr); }
     bool operator!= (const CFX_ByteStringC& other) const {
         return !(*this == other);
     }
@@ skipping 398 matching lines @@
     CFX_WideStringC& operator = (const CFX_WideStringC& src)
     {
         m_Ptr = src.m_Ptr;
         m_Length = src.m_Length;
         return *this;
     }
 
     CFX_WideStringC& operator = (const CFX_WideString& src);
 
     bool operator== (const wchar_t* ptr) const  {
-        return FXSYS_wcslen(ptr) == m_Length &&
+        return (FX_STRSIZE)FXSYS_wcslen(ptr) == m_Length &&
             wmemcmp(ptr, m_Ptr, m_Length) == 0;
     }
     bool operator== (const CFX_WideStringC& str) const  {
         return str.m_Length == m_Length &&
             wmemcmp(str.m_Ptr, m_Ptr, m_Length) == 0;
     }
     bool operator!= (const wchar_t* ptr) const { return !(*this == ptr); }
     bool operator!= (const CFX_WideStringC& str) const {
         return !(*this == str);
     }
@@ skipping 348 matching lines @@
 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(wsStr.c_str(), wsStr.GetLength());
 }
 #endif