Fix some sign comparison warnings.

fpdfsdk/src/javascript/PublicMethods.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 "../../include/javascript/JavaScript.h"
 #include "../../include/javascript/IJavaScript.h"
 #include "../../include/javascript/JS_Define.h"
 #include "../../include/javascript/JS_Object.h"
@@ skipping 1117 matching lines @@
     }
     return TRUE;  // it happens after the last keystroke and before validating,
   }
 
   std::wstring w_strValue2 = w_strValue.c_str();
   std::wstring w_strChange2 = w_strChange.c_str();
   std::wstring w_strSelected;
   if (-1 != pEvent->SelStart())
     w_strSelected = w_strValue2.substr(pEvent->SelStart(),
                                        (pEvent->SelEnd() - pEvent->SelStart()));
-  FX_BOOL bHasSign =
-      (w_strValue2.find('-') != -1) && (w_strSelected.find('-') == -1);
+  bool bHasSign = (w_strValue2.find('-') != std::wstring::npos) &&
+                  (w_strSelected.find('-') == std::wstring::npos);
   if (bHasSign) {
     // can't insert "change" in front to sign postion.
     if (pEvent->SelStart() == 0) {
       FX_BOOL& bRc = pEvent->Rc();
       bRc = FALSE;
       return TRUE;
     }
   }
 
   char cSep = L'.';
 
   switch (iSepStyle) {
     case 0:
     case 1:
       cSep = L'.';
       break;
     case 2:
     case 3:
       cSep = L',';
       break;
   }
 
-  FX_BOOL bHasSep = (w_strValue2.find(cSep) != -1);
+  bool bHasSep = (w_strValue2.find(cSep) != std::wstring::npos);
   for (std::wstring::iterator it = w_strChange2.begin();
        it != w_strChange2.end(); it++) {
     if (*it == cSep) {
       if (bHasSep) {
         FX_BOOL& bRc = pEvent->Rc();
         bRc = FALSE;
         return TRUE;
       }
       bHasSep = TRUE;
       continue;
@@ skipping 961 matching lines @@
     nums.SetElement(nIndex, CJS_Value(isolate, sPart.c_str()));
   }
 
   if (nums.GetLength() > 0)
     vRet = nums;
   else
     vRet.SetNull();
 
   return TRUE;
 }