Clean up XFA code which causes warnings

xfa/fde/xml/fde_xml_imp.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 "xfa/fde/xml/fde_xml_imp.h"
 
 #include <algorithm>
 
@@ skipping 336 matching lines @@
         m_pPrior->m_pNext = pNode;
       } else if (m_pParent) {
         m_pParent->m_pChild = pNode;
       }
       m_pPrior = pNode;
       return TRUE;
     }
     default:
       return FALSE;
   }
-  return FALSE;
 }
 CFDE_XMLNode* CFDE_XMLNode::RemoveNodeItem(CFDE_XMLNode::NodeItem eItem) {
   CFDE_XMLNode* pNode = NULL;
   switch (eItem) {
     case CFDE_XMLNode::NextSibling:
       if (m_pNext) {
         pNode = m_pNext;
         m_pNext = pNode->m_pNext;
         if (m_pNext) {
           m_pNext->m_pPrior = this;
@@ skipping 1705 matching lines @@
     m_BlockBuffer.DeleteTextChars(m_iDataLength - m_iEntityStart, FALSE);
     m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
     m_iEntityStart = -1;
   } else {
     if (m_iEntityStart < 0 && ch == L'&') {
       m_iEntityStart = m_iDataLength - 1;
     }
   }
   m_pStart++;
 }