Use observed pointers in CPDFSDK_AnnotIterator.

fpdfsdk/cpdfsdk_annotiterator.h

-// 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
-
-#ifndef FPDFSDK_CPDFSDK_ANNOTITERATOR_H_
-#define FPDFSDK_CPDFSDK_ANNOTITERATOR_H_
-
-#include <vector>
-
-class CPDFSDK_Annot;
-class CPDFSDK_PageView;
-
-class CPDFSDK_AnnotIterator {
- public:
-  CPDFSDK_AnnotIterator(CPDFSDK_PageView* pPageView, bool bReverse);
-  ~CPDFSDK_AnnotIterator();
-
-  CPDFSDK_Annot* Next();
-
- private:
-  CPDFSDK_Annot* NextAnnot();
-  CPDFSDK_Annot* PrevAnnot();
-
-  std::vector<CPDFSDK_Annot*> m_iteratorAnnotList;
-  const bool m_bReverse;
-  std::size_t m_pos;
-};
-
-#endif  // FPDFSDK_CPDFSDK_ANNOTITERATOR_H_