Watch destruction of widgets around OnAAction() method

fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp

 // Copyright 2016 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/fpdfxfa/include/cpdfxfa_docenvironment.h"
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_string.h"
@@ skipping 520 matching lines @@
     m_pDocument->GetSDKDoc()->GetInterForm()->XfaSetValidationsEnabled(
         bEnabled);
 }
 
 void CPDFXFA_DocEnvironment::SetFocusWidget(CXFA_FFDoc* hDoc,
                                             CXFA_FFWidget* hWidget) {
   if (hDoc != m_pDocument->GetXFADoc())
     return;
 
   if (!hWidget) {
-    m_pDocument->GetSDKDoc()->SetFocusAnnot(nullptr);
+    CPDFSDK_Annot::ObservedPtr pNull;
+    m_pDocument->GetSDKDoc()->SetFocusAnnot(&pNull);
     return;
   }
 
   int pageViewCount = m_pDocument->GetSDKDoc()->GetPageViewCount();
   for (int i = 0; i < pageViewCount; i++) {
     CPDFSDK_PageView* pPageView = m_pDocument->GetSDKDoc()->GetPageView(i);
     if (!pPageView)
       continue;
 
-    CPDFSDK_Annot* pAnnot = pPageView->GetAnnotByXFAWidget(hWidget);
+    CPDFSDK_Annot::ObservedPtr pAnnot(pPageView->GetAnnotByXFAWidget(hWidget));
     if (pAnnot) {
-      m_pDocument->GetSDKDoc()->SetFocusAnnot(pAnnot);
+      m_pDocument->GetSDKDoc()->SetFocusAnnot(&pAnnot);
       break;
     }
   }
 }
 
 void CPDFXFA_DocEnvironment::Print(CXFA_FFDoc* hDoc,
                                    int32_t nStartPage,
                                    int32_t nEndPage,
                                    uint32_t dwOptions) {
   if (hDoc != m_pDocument->GetXFADoc())
@@ skipping 446 matching lines @@
   if (!m_pJSContext) {
     m_pDocument->GetSDKDoc()->GetEnv()->GetJSRuntime()->SetReaderDocument(
         m_pDocument->GetSDKDoc());
     m_pJSContext =
         m_pDocument->GetSDKDoc()->GetEnv()->GetJSRuntime()->NewContext();
   }
 
   return m_pDocument->GetSDKDoc()->GetEnv()->GetJSRuntime()->GetValueByName(
       szPropName, pValue);
 }