Remove { delete this; } anti-pattern from IXFA_WidgetIterator

xfa/fxfa/app/xfa_rendercontext.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/fxfa/include/xfa_rendercontext.h"
 
 #include "xfa/fxfa/include/xfa_ffpageview.h"
 #include "xfa/fxfa/include/xfa_ffwidget.h"
@@ skipping 50 matching lines @@
     m_pWidget = m_pWidgetIterator->MoveToNext();
     iCount++;
     if (iCount > XFA_RENDERCONTEXT_MaxCount && pPause &&
         pPause->NeedToPauseNow()) {
       return XFA_RENDERSTATUS_ToBeContinued;
     }
   }
   return XFA_RENDERSTATUS_Done;
 }
 void CXFA_RenderContext::StopRender() {
-  if (m_pWidgetIterator) {
-    m_pWidgetIterator->Release();
-    m_pWidgetIterator = NULL;
-  }
+  delete m_pWidgetIterator;
+  m_pWidgetIterator = nullptr;
 }