diff --git a/fpdfsdk/cpdfsdk_formfillenvironment.cpp b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
index cb55096..8c5025e 100644
--- a/fpdfsdk/cpdfsdk_formfillenvironment.cpp
+++ b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
@@ -233,7 +233,7 @@
   return m_pFormFiller.get();
 }
 
-void CPDFSDK_FormFillEnvironment::Invalidate(FPDF_PAGE page,
+void CPDFSDK_FormFillEnvironment::Invalidate(UnderlyingPageType* page,
                                              const FX_RECT& rect) {
   if (m_pInfo && m_pInfo->FFI_Invalidate) {
     m_pInfo->FFI_Invalidate(m_pInfo, page, rect.left, rect.top, rect.right,
@@ -242,7 +242,7 @@
 }
 
 void CPDFSDK_FormFillEnvironment::OutputSelectedRect(
-    FPDF_PAGE page,
+    UnderlyingPageType* page,
     const CFX_FloatRect& rect) {
   if (m_pInfo && m_pInfo->FFI_OutputSelectedRect) {
     m_pInfo->FFI_OutputSelectedRect(m_pInfo, page, rect.left, rect.top,
@@ -301,14 +301,15 @@
   return (nFlag & FWL_EVENTFLAG_AltKey) != 0;
 }
 
-FPDF_PAGE CPDFSDK_FormFillEnvironment::GetPage(FPDF_DOCUMENT document,
+FPDF_PAGE CPDFSDK_FormFillEnvironment::GetPage(UnderlyingDocumentType* document,
                                                int nPageIndex) {
   if (m_pInfo && m_pInfo->FFI_GetPage)
     return m_pInfo->FFI_GetPage(m_pInfo, document, nPageIndex);
   return nullptr;
 }
 
-FPDF_PAGE CPDFSDK_FormFillEnvironment::GetCurrentPage(FPDF_DOCUMENT document) {
+FPDF_PAGE CPDFSDK_FormFillEnvironment::GetCurrentPage(
+    UnderlyingDocumentType* document) {
   if (m_pInfo && m_pInfo->FFI_GetCurrentPage)
     return m_pInfo->FFI_GetCurrentPage(m_pInfo, document);
   return nullptr;
@@ -343,7 +344,7 @@
 }
 
 #ifdef PDF_ENABLE_XFA
-void CPDFSDK_FormFillEnvironment::DisplayCaret(FPDF_PAGE page,
+void CPDFSDK_FormFillEnvironment::DisplayCaret(CPDFXFA_Page* page,
                                                FPDF_BOOL bVisible,
                                                double left,
                                                double top,
@@ -355,13 +356,14 @@
   }
 }
 
-int CPDFSDK_FormFillEnvironment::GetCurrentPageIndex(FPDF_DOCUMENT document) {
+int CPDFSDK_FormFillEnvironment::GetCurrentPageIndex(
+    CPDFXFA_Context* document) {
   if (!m_pInfo || !m_pInfo->FFI_GetCurrentPageIndex)
     return -1;
   return m_pInfo->FFI_GetCurrentPageIndex(m_pInfo, document);
 }
 
-void CPDFSDK_FormFillEnvironment::SetCurrentPage(FPDF_DOCUMENT document,
+void CPDFSDK_FormFillEnvironment::SetCurrentPage(CPDFXFA_Context* document,
                                                  int iCurPage) {
   if (m_pInfo && m_pInfo->FFI_SetCurrentPage)
     m_pInfo->FFI_SetCurrentPage(m_pInfo, document, iCurPage);
@@ -385,7 +387,7 @@
                                      nActualLen / sizeof(uint16_t));
 }
 
-void CPDFSDK_FormFillEnvironment::GotoURL(FPDF_DOCUMENT document,
+void CPDFSDK_FormFillEnvironment::GotoURL(CPDFXFA_Context* document,
                                           const CFX_WideStringC& wsURL) {
   if (!m_pInfo || !m_pInfo->FFI_GotoURL)
     return;
@@ -396,7 +398,7 @@
   bsTo.ReleaseBuffer();
 }
 
-void CPDFSDK_FormFillEnvironment::GetPageViewRect(FPDF_PAGE page,
+void CPDFSDK_FormFillEnvironment::GetPageViewRect(CPDFXFA_Page* page,
                                                   FS_RECTF& dstRect) {
   if (!m_pInfo || !m_pInfo->FFI_GetPageViewRect)
     return;
@@ -413,7 +415,7 @@
   dstRect.right = static_cast<float>(right);
 }
 
-bool CPDFSDK_FormFillEnvironment::PopupMenu(FPDF_PAGE page,
+bool CPDFSDK_FormFillEnvironment::PopupMenu(CPDFXFA_Page* page,
                                             FPDF_WIDGET hWidget,
                                             int menuFlag,
                                             CFX_PointF pt) {
diff --git a/fpdfsdk/cpdfsdk_formfillenvironment.h b/fpdfsdk/cpdfsdk_formfillenvironment.h
index 0462426..91141e5 100644
--- a/fpdfsdk/cpdfsdk_formfillenvironment.h
+++ b/fpdfsdk/cpdfsdk_formfillenvironment.h
@@ -79,8 +79,8 @@
   void ProcJavascriptFun();
   bool ProcOpenAction();
 
-  void Invalidate(FPDF_PAGE page, const FX_RECT& rect);
-  void OutputSelectedRect(FPDF_PAGE page, const CFX_FloatRect& rect);
+  void Invalidate(UnderlyingPageType* page, const FX_RECT& rect);
+  void OutputSelectedRect(UnderlyingPageType* page, const CFX_FloatRect& rect);
 
   void SetCursor(int nCursorType);
   int SetTimer(int uElapse, TimerCallback lpTimerFunc);
@@ -92,8 +92,8 @@
   bool IsCTRLKeyDown(uint32_t nFlag) const;
   bool IsALTKeyDown(uint32_t nFlag) const;
 
-  FPDF_PAGE GetPage(FPDF_DOCUMENT document, int nPageIndex);
-  FPDF_PAGE GetCurrentPage(FPDF_DOCUMENT document);
+  FPDF_PAGE GetPage(UnderlyingDocumentType* document, int nPageIndex);
+  FPDF_PAGE GetCurrentPage(UnderlyingDocumentType* document);
 
   void ExecuteNamedAction(const char* namedAction);
   void OnSetFieldInputFocus(FPDF_WIDESTRING focusText,
@@ -119,22 +119,22 @@
 
   int GetPageViewCount() const { return m_PageMap.size(); }
 
-  void DisplayCaret(FPDF_PAGE page,
+  void DisplayCaret(CPDFXFA_Page* page,
                     FPDF_BOOL bVisible,
                     double left,
                     double top,
                     double right,
                     double bottom);
-  int GetCurrentPageIndex(FPDF_DOCUMENT document);
-  void SetCurrentPage(FPDF_DOCUMENT document, int iCurPage);
+  int GetCurrentPageIndex(CPDFXFA_Context* document);
+  void SetCurrentPage(CPDFXFA_Context* document, int iCurPage);
 
   // TODO(dsinclair): This should probably change to PDFium?
   CFX_WideString FFI_GetAppName() const { return CFX_WideString(L"Acrobat"); }
 
   CFX_WideString GetPlatform();
-  void GotoURL(FPDF_DOCUMENT document, const CFX_WideStringC& wsURL);
-  void GetPageViewRect(FPDF_PAGE page, FS_RECTF& dstRect);
-  bool PopupMenu(FPDF_PAGE page,
+  void GotoURL(CPDFXFA_Context* document, const CFX_WideStringC& wsURL);
+  void GetPageViewRect(CPDFXFA_Page* page, FS_RECTF& dstRect);
+  bool PopupMenu(CPDFXFA_Page* page,
                  FPDF_WIDGET hWidget,
                  int menuFlag,
                  CFX_PointF pt);
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
index 4695c64..28badc4 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
@@ -66,7 +66,7 @@
   if (!pFormFillEnv)
     return;
 
-  pFormFillEnv->Invalidate(static_cast<FPDF_PAGE>(pPage.Get()),
+  pFormFillEnv->Invalidate(pPage.Get(),
                            CFX_FloatRect::FromCFXRectF(rt).ToFxRect());
 }
 
@@ -98,9 +98,8 @@
     return;
 
   CFX_FloatRect rcCaret = CFX_FloatRect::FromCFXRectF(*pRtAnchor);
-  pFormFillEnv->DisplayCaret(static_cast<FPDF_PAGE>(pPage.Get()), bVisible,
-                             rcCaret.left, rcCaret.top, rcCaret.right,
-                             rcCaret.bottom);
+  pFormFillEnv->DisplayCaret(pPage.Get(), bVisible, rcCaret.left, rcCaret.top,
+                             rcCaret.right, rcCaret.bottom);
 }
 
 bool CPDFXFA_DocEnvironment::GetPopupPos(CXFA_FFWidget* hWidget,
@@ -344,7 +343,7 @@
   if (!pFormFillEnv)
     return -1;
 
-  return pFormFillEnv->GetCurrentPageIndex(this);
+  return pFormFillEnv->GetCurrentPageIndex(m_pContext.Get());
 }
 
 void CPDFXFA_DocEnvironment::SetCurrentPage(CXFA_FFDoc* hDoc,
@@ -358,7 +357,7 @@
   CPDFSDK_FormFillEnvironment* pFormFillEnv = m_pContext->GetFormFillEnv();
   if (!pFormFillEnv)
     return;
-  pFormFillEnv->SetCurrentPage(this, iCurPage);
+  pFormFillEnv->SetCurrentPage(m_pContext.Get(), iCurPage);
 }
 
 bool CPDFXFA_DocEnvironment::IsCalculationsEnabled(CXFA_FFDoc* hDoc) {
@@ -518,7 +517,7 @@
     return;
 
   CFX_WideStringC str(bsURL.c_str());
-  pFormFillEnv->GotoURL(this, str);
+  pFormFillEnv->GotoURL(m_pContext.Get(), str);
 }
 
 bool CPDFXFA_DocEnvironment::IsValidationsEnabled(CXFA_FFDoc* hDoc) {