Simplify UTF16LE_Encode and add unittest.

fpdfsdk/src/fpdfdoc.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/fsdk_define.h"
 #include "../include/fpdfdoc.h"
 
 static int THISMODULE = 0;
@@ skipping 35 matching lines @@
     CPDF_Bookmark bookmark = CPDF_Bookmark((CPDF_Dictionary*)pDict);
     return tree.GetNextSibling(bookmark).GetDict();
 }
 
 DLLEXPORT unsigned long STDCALL FPDFBookmark_GetTitle(FPDF_BOOKMARK pDict, void* buffer, unsigned long buflen)
 {
     if (!pDict)
         return 0;
     CPDF_Bookmark bookmark((CPDF_Dictionary*)pDict);
     CFX_WideString title = bookmark.GetTitle();
-    CFX_ByteString encodedTitle = title.UTF16LE_Encode(FALSE);
+    CFX_ByteString encodedTitle = title.UTF16LE_Encode();
     unsigned long len = encodedTitle.GetLength();
-    if (buffer && buflen >= len + 2) {
+    if (buffer && buflen >= len) {
         FXSYS_memcpy(buffer, encodedTitle.c_str(), len);
-        ((FX_BYTE*)buffer)[len] = 0;
-        ((FX_BYTE*)buffer)[len + 1] = 0;
     }
-    return len + 2;
+    return len;
 }
 
 DLLEXPORT FPDF_BOOKMARK STDCALL FPDFBookmark_Find(FPDF_DOCUMENT document, FPDF_WIDESTRING title)
 {
         if (!document)
                 return NULL;
         if (!title || title[0] == 0)
                 return NULL;
         CPDF_Document* pDoc = (CPDF_Document*)document;
         CPDF_BookmarkTree tree(pDoc);
@@ skipping 211 matching lines @@
                 return 0;
         CPDF_Document* pDoc = (CPDF_Document*)doc;
         // Get info dictionary
         CPDF_Dictionary* pInfo = pDoc->GetInfo();
         if (!pInfo)
                 return 0;
         CFX_WideString text = pInfo->GetUnicodeText(tag);
         // Use UTF-16LE encoding
         CFX_ByteString encodedText = text.UTF16LE_Encode();
         unsigned long len = encodedText.GetLength();
-        if (buffer && buflen >= len + 2) {
+        if (buffer && buflen >= len) {
                 FXSYS_memcpy(buffer, encodedText.c_str(), len);
-                // use double zero as trailer
-                ((FX_BYTE*)buffer)[len] = 0;
-                ((FX_BYTE*)buffer)[len + 1] = 0;
         }
-        return len+2;
+        return len;
 }