Fix uninitialized variable introduced by previous refactoring.

fpdfsdk/src/fsdk_mgr.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 <algorithm>
 
 #include "../../public/fpdf_ext.h"
 #include "../../third_party/base/nonstd_unique_ptr.h"
@@ skipping 369 matching lines @@
 }
 
 CFFL_IFormFiller* CPDFDoc_Environment::GetIFormFiller() {
   if (!m_pIFormFiller)
     m_pIFormFiller.reset(new CFFL_IFormFiller(this));
   return m_pIFormFiller.get();
 }
 
 CPDFSDK_Document::CPDFSDK_Document(CPDF_Document* pDoc,
                                    CPDFDoc_Environment* pEnv)
-    : m_pDoc(pDoc), m_pFocusAnnot(nullptr), m_pEnv(pEnv), m_bChangeMask(FALSE) {
+    : m_pDoc(pDoc),
+      m_pFocusAnnot(nullptr),
+      m_pEnv(pEnv),
+      m_bChangeMask(FALSE),
+      m_bBeingDestroyed(FALSE) {
 }
 
 CPDFSDK_Document::~CPDFSDK_Document() {
   m_bBeingDestroyed = TRUE;
 
   for (auto& it : m_pageMap)
     it.second->KillFocusAnnotIfNeeded();
 
   for (auto& it : m_pageMap)
     delete it.second;
@@ skipping 521 matching lines @@
   CPDFSDK_Annot* pFocusAnnot = m_pSDKDoc->GetFocusAnnot();
   if (!pFocusAnnot)
     return nullptr;
 
   for (CPDFSDK_Annot* pAnnot : m_fxAnnotArray) {
     if (pAnnot == pFocusAnnot)
       return pAnnot;
   }
   return nullptr;
 }