Watch destruction of widgets around OnAAction() method

fpdfsdk/javascript/Field.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 "fpdfsdk/javascript/Field.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 3204 matching lines @@
           if (pTempWidget->GetPDFPage() == pCurPageView->GetPDFPage()) {
             pWidget = pTempWidget;
             break;
           }
         }
       }
     }
   }
 
   if (pWidget) {
-    m_pDocument->SetFocusAnnot(pWidget);
+    CPDFSDK_Annot::ObservedPtr pObserved(pWidget);
+    m_pDocument->SetFocusAnnot(&pObserved);
   }
 
   return TRUE;
 }
 
 FX_BOOL Field::setItems(IJS_Context* cc,
                         const std::vector<CJS_Value>& params,
                         CJS_Value& vRet,
                         CFX_WideString& sError) {
   return TRUE;
@@ skipping 255 matching lines @@
   }
 }
 
 void Field::AddField(CPDFSDK_Document* pDocument,
                      int nPageIndex,
                      int nFieldType,
                      const CFX_WideString& sName,
                      const CFX_FloatRect& rcCoords) {
   // Not supported.
 }