Make creation of CPDFSDK_Document clearer

fpdfsdk/cpdfsdk_environment.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/include/cpdfsdk_environment.h"
 
 #include "fpdfsdk/formfiller/cffl_interactiveformfiller.h"
 #include "fpdfsdk/include/cpdfsdk_annothandlermgr.h"
+#include "fpdfsdk/include/cpdfsdk_document.h"
 #include "fpdfsdk/include/fsdk_actionhandler.h"
 #include "fpdfsdk/javascript/ijs_runtime.h"
 
 #ifdef PDF_ENABLE_XFA
 #include "fpdfsdk/fpdfxfa/include/fpdfxfa_app.h"
 #endif  // PDF_ENABLE_XFA
 
 namespace {
 
 // NOTE: |bsUTF16LE| must outlive the use of the result. Care must be taken
 // since modifying the result would impact |bsUTF16LE|.
 FPDF_WIDESTRING AsFPDFWideString(CFX_ByteString* bsUTF16LE) {
   return reinterpret_cast<FPDF_WIDESTRING>(
       bsUTF16LE->GetBuffer(bsUTF16LE->GetLength()));
 }
 
 }  // namespace
 
 CPDFSDK_Environment::CPDFSDK_Environment(UnderlyingDocumentType* pDoc,
                                          FPDF_FORMFILLINFO* pFFinfo)
-    : m_pInfo(pFFinfo), m_pSDKDoc(nullptr), m_pUnderlyingDoc(pDoc) {
-  m_pSysHandler.reset(new CFX_SystemHandler(this));
-}
+    : m_pInfo(pFFinfo),
+      m_pSDKDoc(new CPDFSDK_Document(pDoc, this)),
+      m_pUnderlyingDoc(pDoc),
+      m_pSysHandler(new CFX_SystemHandler(this)) {}
 
 CPDFSDK_Environment::~CPDFSDK_Environment() {
 #ifdef PDF_ENABLE_XFA
   CPDFXFA_App* pProvider = CPDFXFA_App::GetInstance();
   if (pProvider->m_pEnvList.GetSize() == 0)
     pProvider->SetJavaScriptInitialized(FALSE);
 #endif  // PDF_ENABLE_XFA
   if (m_pInfo && m_pInfo->Release)
     m_pInfo->Release(m_pInfo);
 }
@@ skipping 161 matching lines @@
   if (!m_pActionHandler)
     m_pActionHandler.reset(new CPDFSDK_ActionHandler());
   return m_pActionHandler.get();
 }
 
 CFFL_InteractiveFormFiller* CPDFSDK_Environment::GetInteractiveFormFiller() {
   if (!m_pFormFiller)
     m_pFormFiller.reset(new CFFL_InteractiveFormFiller(this));
   return m_pFormFiller.get();
 }