diff --git a/fpdfsdk/formfiller/cffl_interactiveformfiller.h b/fpdfsdk/formfiller/cffl_interactiveformfiller.h
index d663100..11b0f2f 100644
--- a/fpdfsdk/formfiller/cffl_interactiveformfiller.h
+++ b/fpdfsdk/formfiller/cffl_interactiveformfiller.h
@@ -14,8 +14,7 @@
 #include "core/fxcrt/observed_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
 #include "fpdfsdk/cpdfsdk_annot.h"
-#include "fpdfsdk/pwl/cpwl_edit.h"
-#include "fpdfsdk/pwl/cpwl_wnd.h"
+#include "fpdfsdk/pwl/ipwl_fillernotify.h"
 #include "fpdfsdk/pwl/ipwl_systemhandler.h"
 
 class CFFL_FormFiller;
@@ -23,7 +22,7 @@
 class CPDFSDK_PageView;
 class CPDFSDK_Widget;
 
-class CFFL_InteractiveFormFiller final : public IPWL_Filler_Notify {
+class CFFL_InteractiveFormFiller final : public IPWL_FillerNotify {
  public:
   explicit CFFL_InteractiveFormFiller(
       CPDFSDK_FormFillEnvironment* pFormFillEnv);
@@ -125,7 +124,7 @@
   using WidgetToFormFillerMap =
       std::map<CPDFSDK_Annot*, std::unique_ptr<CFFL_FormFiller>>;
 
-  // IPWL_Filler_Notify:
+  // IPWL_FillerNotify:
   void QueryWherePopup(const IPWL_SystemHandler::PerWindowData* pAttached,
                        float fPopupMin,
                        float fPopupMax,
@@ -177,7 +176,7 @@
   CFFL_PrivateData(const CFFL_PrivateData& that);
   ~CFFL_PrivateData() override;
 
-  // CPWL_Wnd::PrivateData:
+  // IPWL_SystemHandler::PerWindowData:
   std::unique_ptr<IPWL_SystemHandler::PerWindowData> Clone() const override;
 
   CPDFSDK_Widget* GetWidget() const { return pWidget.Get(); }
diff --git a/fpdfsdk/formfiller/cffl_textfield.cpp b/fpdfsdk/formfiller/cffl_textfield.cpp
index 93ec9fe..fd1c719 100644
--- a/fpdfsdk/formfiller/cffl_textfield.cpp
+++ b/fpdfsdk/formfiller/cffl_textfield.cpp
@@ -12,6 +12,7 @@
 #include "core/fpdfdoc/cba_fontmap.h"
 #include "fpdfsdk/cpdfsdk_formfillenvironment.h"
 #include "fpdfsdk/cpdfsdk_widget.h"
+#include "fpdfsdk/pwl/cpwl_edit.h"
 #include "public/fpdf_fwlevent.h"
 
 namespace {
diff --git a/fpdfsdk/pwl/BUILD.gn b/fpdfsdk/pwl/BUILD.gn
index 17c0c95..fa8df3c 100644
--- a/fpdfsdk/pwl/BUILD.gn
+++ b/fpdfsdk/pwl/BUILD.gn
@@ -31,6 +31,7 @@
     "cpwl_special_button.h",
     "cpwl_wnd.cpp",
     "cpwl_wnd.h",
+    "ipwl_fillernotify.h",
     "ipwl_systemhandler.h",
   ]
   configs += [ "../../:pdfium_core_config" ]
diff --git a/fpdfsdk/pwl/cpwl_combo_box.cpp b/fpdfsdk/pwl/cpwl_combo_box.cpp
index 0595969..af5dffc 100644
--- a/fpdfsdk/pwl/cpwl_combo_box.cpp
+++ b/fpdfsdk/pwl/cpwl_combo_box.cpp
@@ -13,11 +13,9 @@
 #include "core/fxge/cfx_fillrenderoptions.h"
 #include "core/fxge/cfx_pathdata.h"
 #include "core/fxge/cfx_renderdevice.h"
-#include "fpdfsdk/pwl/cpwl_edit.h"
 #include "fpdfsdk/pwl/cpwl_edit_ctrl.h"
-#include "fpdfsdk/pwl/cpwl_list_box.h"
 #include "fpdfsdk/pwl/cpwl_list_ctrl.h"
-#include "fpdfsdk/pwl/cpwl_wnd.h"
+#include "fpdfsdk/pwl/ipwl_fillernotify.h"
 #include "public/fpdf_fwlevent.h"
 
 namespace {
@@ -607,7 +605,7 @@
   m_nSelectItem = m_pList->GetCurSel();
 }
 
-void CPWL_ComboBox::SetFillerNotify(IPWL_Filler_Notify* pNotify) {
+void CPWL_ComboBox::SetFillerNotify(IPWL_FillerNotify* pNotify) {
   m_pFillerNotify = pNotify;
 
   if (m_pEdit)
diff --git a/fpdfsdk/pwl/cpwl_combo_box.h b/fpdfsdk/pwl/cpwl_combo_box.h
index cf1a875..1624af2 100644
--- a/fpdfsdk/pwl/cpwl_combo_box.h
+++ b/fpdfsdk/pwl/cpwl_combo_box.h
@@ -15,6 +15,8 @@
 #include "fpdfsdk/pwl/cpwl_list_box.h"
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
+class IPWL_FillerNotify;
+
 class CPWL_CBListBox final : public CPWL_ListBox {
  public:
   CPWL_CBListBox(
@@ -74,7 +76,7 @@
   bool Undo() override;
   bool Redo() override;
 
-  void SetFillerNotify(IPWL_Filler_Notify* pNotify);
+  void SetFillerNotify(IPWL_FillerNotify* pNotify);
 
   void SetText(const WideString& text);
   void AddString(const WideString& str);
@@ -104,7 +106,7 @@
   bool m_bPopup = false;
   bool m_bBottom = true;
   int32_t m_nSelectItem = -1;
-  UnownedPtr<IPWL_Filler_Notify> m_pFillerNotify;
+  UnownedPtr<IPWL_FillerNotify> m_pFillerNotify;
   UnownedPtr<CFFL_FormFiller> m_pFormFiller;
 };
 
diff --git a/fpdfsdk/pwl/cpwl_edit.cpp b/fpdfsdk/pwl/cpwl_edit.cpp
index c47bccb..b26fbbc 100644
--- a/fpdfsdk/pwl/cpwl_edit.cpp
+++ b/fpdfsdk/pwl/cpwl_edit.cpp
@@ -25,6 +25,7 @@
 #include "fpdfsdk/pwl/cpwl_edit_impl.h"
 #include "fpdfsdk/pwl/cpwl_scroll_bar.h"
 #include "fpdfsdk/pwl/cpwl_wnd.h"
+#include "fpdfsdk/pwl/ipwl_fillernotify.h"
 #include "public/fpdf_fwlevent.h"
 
 CPWL_Edit::CPWL_Edit(
diff --git a/fpdfsdk/pwl/cpwl_edit.h b/fpdfsdk/pwl/cpwl_edit.h
index 8315527..06e1ae2 100644
--- a/fpdfsdk/pwl/cpwl_edit.h
+++ b/fpdfsdk/pwl/cpwl_edit.h
@@ -16,36 +16,7 @@
 #include "fpdfsdk/pwl/ipwl_systemhandler.h"
 
 class CPDF_Font;
-
-class IPWL_Filler_Notify {
- public:
-  virtual ~IPWL_Filler_Notify() = default;
-
-  // Must write to |bBottom| and |fPopupRet|.
-  virtual void QueryWherePopup(
-      const IPWL_SystemHandler::PerWindowData* pAttached,
-      float fPopupMin,
-      float fPopupMax,
-      bool* bBottom,
-      float* fPopupRet) = 0;
-
-  virtual std::pair<bool, bool> OnBeforeKeyStroke(
-      const IPWL_SystemHandler::PerWindowData* pAttached,
-      WideString& strChange,
-      const WideString& strChangeEx,
-      int nSelStart,
-      int nSelEnd,
-      bool bKeyDown,
-      uint32_t nFlag) = 0;
-
-  virtual bool OnPopupPreOpen(
-      const IPWL_SystemHandler::PerWindowData* pAttached,
-      uint32_t nFlag) = 0;
-
-  virtual bool OnPopupPostOpen(
-      const IPWL_SystemHandler::PerWindowData* pAttached,
-      uint32_t nFlag) = 0;
-};
+class IPWL_FillerNotify;
 
 class CPWL_Edit final : public CPWL_EditCtrl {
  public:
@@ -90,7 +61,7 @@
                                         const CFX_FloatRect& rcPlate,
                                         int32_t nCharArray);
 
-  void SetFillerNotify(IPWL_Filler_Notify* pNotify) {
+  void SetFillerNotify(IPWL_FillerNotify* pNotify) {
     m_pFillerNotify = pNotify;
   }
 
@@ -128,7 +99,7 @@
 
   bool m_bFocus = false;
   CFX_FloatRect m_rcOldWindow;
-  UnownedPtr<IPWL_Filler_Notify> m_pFillerNotify;
+  UnownedPtr<IPWL_FillerNotify> m_pFillerNotify;
   UnownedPtr<CFFL_FormFiller> m_pFormFiller;
 };
 
diff --git a/fpdfsdk/pwl/cpwl_list_box.cpp b/fpdfsdk/pwl/cpwl_list_box.cpp
index 3c8d01d..ca5adde 100644
--- a/fpdfsdk/pwl/cpwl_list_box.cpp
+++ b/fpdfsdk/pwl/cpwl_list_box.cpp
@@ -13,9 +13,8 @@
 #include "fpdfsdk/pwl/cpwl_edit.h"
 #include "fpdfsdk/pwl/cpwl_edit_ctrl.h"
 #include "fpdfsdk/pwl/cpwl_edit_impl.h"
-#include "fpdfsdk/pwl/cpwl_list_ctrl.h"
 #include "fpdfsdk/pwl/cpwl_scroll_bar.h"
-#include "fpdfsdk/pwl/cpwl_wnd.h"
+#include "fpdfsdk/pwl/ipwl_fillernotify.h"
 #include "public/fpdf_fwlevent.h"
 
 CPWL_ListBox::CPWL_ListBox(
diff --git a/fpdfsdk/pwl/cpwl_list_box.h b/fpdfsdk/pwl/cpwl_list_box.h
index a5484c3..b3dc594 100644
--- a/fpdfsdk/pwl/cpwl_list_box.h
+++ b/fpdfsdk/pwl/cpwl_list_box.h
@@ -13,7 +13,7 @@
 #include "fpdfsdk/pwl/cpwl_list_ctrl.h"
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
-class IPWL_Filler_Notify;
+class IPWL_FillerNotify;
 struct CPVT_WordPlace;
 
 class CPWL_ListBox : public CPWL_Wnd, public CPWL_ListCtrl::NotifyIface {
@@ -78,7 +78,7 @@
   float GetFirstHeight() const;
   CFX_FloatRect GetListRect() const;
 
-  void SetFillerNotify(IPWL_Filler_Notify* pNotify) {
+  void SetFillerNotify(IPWL_FillerNotify* pNotify) {
     m_pFillerNotify = pNotify;
   }
 
@@ -88,7 +88,7 @@
   bool m_bMouseDown = false;
   bool m_bHoverSel = false;
   std::unique_ptr<CPWL_ListCtrl> m_pListCtrl;
-  UnownedPtr<IPWL_Filler_Notify> m_pFillerNotify;
+  UnownedPtr<IPWL_FillerNotify> m_pFillerNotify;
 
  private:
   UnownedPtr<CFFL_FormFiller> m_pFormFiller;
diff --git a/fpdfsdk/pwl/ipwl_fillernotify.h b/fpdfsdk/pwl/ipwl_fillernotify.h
new file mode 100644
index 0000000..e968633
--- /dev/null
+++ b/fpdfsdk/pwl/ipwl_fillernotify.h
@@ -0,0 +1,45 @@
+// Copyright 2020 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_PWL_IFWL_FILLERNOTIFY_H_
+#define FPDFSDK_PWL_IFWL_FILLERNOTIFY_H_
+
+#include <utility>
+
+#include "core/fxcrt/fx_string.h"
+#include "fpdfsdk/pwl/ipwl_systemhandler.h"
+
+class IPWL_FillerNotify {
+ public:
+  virtual ~IPWL_FillerNotify() = default;
+
+  // Must write to |bBottom| and |fPopupRet|.
+  virtual void QueryWherePopup(
+      const IPWL_SystemHandler::PerWindowData* pAttached,
+      float fPopupMin,
+      float fPopupMax,
+      bool* bBottom,
+      float* fPopupRet) = 0;
+
+  virtual std::pair<bool, bool> OnBeforeKeyStroke(
+      const IPWL_SystemHandler::PerWindowData* pAttached,
+      WideString& strChange,
+      const WideString& strChangeEx,
+      int nSelStart,
+      int nSelEnd,
+      bool bKeyDown,
+      uint32_t nFlag) = 0;
+
+  virtual bool OnPopupPreOpen(
+      const IPWL_SystemHandler::PerWindowData* pAttached,
+      uint32_t nFlag) = 0;
+
+  virtual bool OnPopupPostOpen(
+      const IPWL_SystemHandler::PerWindowData* pAttached,
+      uint32_t nFlag) = 0;
+};
+
+#endif  // FPDFSDK_PWL_IFWL_FILLERNOTIFY_H_