Getting rid of more (FX_LPCWSTR) casts and fixing two bugs revealed by this.

fpdfsdk/src/javascript/app.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 795 matching lines @@
         
         
 
         CJS_Runtime* pRuntime = pContext->GetJSRuntime();
         ASSERT(pRuntime != NULL);
 
         CPDFDoc_Environment* pApp = pContext->GetReaderApp();
         ASSERT(pApp != NULL);
 
         pRuntime->BeginBlock();
-        pApp->JS_docmailForm(NULL, 0, bUI, (FX_LPCWSTR)cTo, (FX_LPCWSTR)cSubject, (FX_LPCWSTR)cCc, (FX_LPCWSTR)cBcc, (FX_LPCWSTR)cMsg);
+        pApp->JS_docmailForm(NULL, 0, bUI, cTo.c_str(), cSubject.c_str(), cCc.c_str(), cBcc.c_str(), cMsg.c_str());
         ///////////////////////////////////////////////////////////////////////////////////////////////
         pRuntime->EndBlock();
 
         //return bRet;
         return FALSE;
 }
 
 FX_BOOL app::launchURL(OBJ_METHOD_PARAMS)
 {
         if (IsSafeMode(cc)) return TRUE;
@@ skipping 286 matching lines @@
 FX_BOOL app::media(OBJ_PROP_PARAMS)
 {
         return FALSE;
 }
 
 FX_BOOL app::execDialog(OBJ_METHOD_PARAMS)
 {
         return TRUE;
 }