Make conversion between CPDF_Action and its dictionary explicit

core/src/fpdfdoc/doc_bookmark.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/fpdfdoc/fpdf_doc.h"
 CPDF_Bookmark CPDF_BookmarkTree::GetFirstChild(const CPDF_Bookmark& parent) const
 {
     if (!parent.m_pDict) {
@@ skipping 68 matching lines @@
         CFX_ByteStringC name = pDest->GetString();
         return name_tree.LookupNamedDest(pDocument, name);
     } else if (pDest->GetType() == PDFOBJ_ARRAY) {
         return (CPDF_Array*)pDest;
     }
     return NULL;
 }
 CPDF_Action CPDF_Bookmark::GetAction() const
 {
     if (!m_pDict) {
-        return NULL;
+        return CPDF_Action();
     }
-    return m_pDict->GetDict("A");
+    return CPDF_Action(m_pDict->GetDict("A"));
 }