diff --git a/fpdfsdk/cpdfsdk_formfillenvironment.cpp b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
index da34286..c5f9aeb 100644
--- a/fpdfsdk/cpdfsdk_formfillenvironment.cpp
+++ b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
@@ -19,6 +19,7 @@
 #include "fpdfsdk/formfiller/cffl_interactiveformfiller.h"
 #include "fxjs/ijs_runtime.h"
 #include "third_party/base/ptr_util.h"
+#include "third_party/base/stl_util.h"
 
 #ifdef PDF_ENABLE_XFA
 #include "fpdfsdk/fpdfxfa/cpdfxfa_context.h"
@@ -37,10 +38,7 @@
     FPDF_FORMFILLINFO* pFFinfo)
     : m_pInfo(pFFinfo),
       m_pCPDFDoc(pDoc),
-      m_pSysHandler(pdfium::MakeUnique<CFX_SystemHandler>(this)),
-      m_bChangeMask(false),
-      m_bBeingDestroyed(false),
-      m_SaveCalled(nullptr) {}
+      m_pSysHandler(pdfium::MakeUnique<CFX_SystemHandler>(this)) {}
 
 CPDFSDK_FormFillEnvironment::~CPDFSDK_FormFillEnvironment() {
   m_bBeingDestroyed = true;
@@ -714,6 +712,10 @@
     return nullptr;
   return static_cast<CPDFXFA_Context*>(m_pCPDFDoc->GetExtension());
 }
+
+int CPDFSDK_FormFillEnvironment::GetPageViewCount() const {
+  return pdfium::CollectionSize<int>(m_PageMap);
+}
 #endif  // PDF_ENABLE_XFA
 
 int CPDFSDK_FormFillEnvironment::GetPageCount() const {
diff --git a/fpdfsdk/cpdfsdk_formfillenvironment.h b/fpdfsdk/cpdfsdk_formfillenvironment.h
index 1cf078e..8590b34 100644
--- a/fpdfsdk/cpdfsdk_formfillenvironment.h
+++ b/fpdfsdk/cpdfsdk_formfillenvironment.h
@@ -115,7 +115,7 @@
 
 #ifdef PDF_ENABLE_XFA
   CPDFXFA_Context* GetXFAContext() const;
-  int GetPageViewCount() const { return m_PageMap.size(); }
+  int GetPageViewCount() const;
 
   void DisplayCaret(CPDFXFA_Page* page,
                     FPDF_BOOL bVisible,
@@ -224,9 +224,9 @@
   UnownedPtr<CPDF_Document> const m_pCPDFDoc;
   std::unique_ptr<CFFL_InteractiveFormFiller> m_pFormFiller;
   std::unique_ptr<CFX_SystemHandler> m_pSysHandler;
-  bool m_bChangeMask;
-  bool m_bBeingDestroyed;
-  FORM_SAVECALLED m_SaveCalled;
+  bool m_bChangeMask = false;
+  bool m_bBeingDestroyed = false;
+  FORM_SAVECALLED m_SaveCalled = nullptr;
 };
 
 #endif  // FPDFSDK_CPDFSDK_FORMFILLENVIRONMENT_H_