diff --git a/fpdfsdk/formfiller/cba_fontmap.cpp b/fpdfsdk/formfiller/cba_fontmap.cpp
index c3ab2b8..625ce46 100644
--- a/fpdfsdk/formfiller/cba_fontmap.cpp
+++ b/fpdfsdk/formfiller/cba_fontmap.cpp
@@ -68,7 +68,7 @@
 }
 
 void CBA_FontMap::SetDefaultFont(CPDF_Font* pFont,
-                                 const CFX_ByteString& sFontName) {
+                                 const ByteString& sFontName) {
   ASSERT(pFont);
 
   if (m_pDefaultFont)
@@ -83,7 +83,7 @@
   AddFontData(m_pDefaultFont.Get(), m_sDefaultFontName, nCharset);
 }
 
-CPDF_Font* CBA_FontMap::FindFontSameCharset(CFX_ByteString* sFontAlias,
+CPDF_Font* CBA_FontMap::FindFontSameCharset(ByteString* sFontAlias,
                                             int32_t nCharset) {
   if (m_pAnnotDict->GetStringFor("Subtype") != "Widget")
     return nullptr;
@@ -109,7 +109,7 @@
 }
 
 CPDF_Font* CBA_FontMap::FindResFontSameCharset(CPDF_Dictionary* pResDict,
-                                               CFX_ByteString* sFontAlias,
+                                               ByteString* sFontAlias,
                                                int32_t nCharset) {
   if (!pResDict)
     return nullptr;
@@ -121,7 +121,7 @@
   CPDF_Document* pDocument = GetDocument();
   CPDF_Font* pFind = nullptr;
   for (const auto& it : *pFonts) {
-    const CFX_ByteString& csKey = it.first;
+    const ByteString& csKey = it.first;
     if (!it.second)
       continue;
 
@@ -145,13 +145,12 @@
   return pFind;
 }
 
-void CBA_FontMap::AddedFont(CPDF_Font* pFont,
-                            const CFX_ByteString& sFontAlias) {
+void CBA_FontMap::AddedFont(CPDF_Font* pFont, const ByteString& sFontAlias) {
   AddFontToAnnotDict(pFont, sFontAlias);
 }
 
 void CBA_FontMap::AddFontToAnnotDict(CPDF_Font* pFont,
-                                     const CFX_ByteString& sAlias) {
+                                     const ByteString& sAlias) {
   if (!pFont)
     return;
 
@@ -194,7 +193,7 @@
   }
 }
 
-CPDF_Font* CBA_FontMap::GetAnnotDefaultFont(CFX_ByteString* sAlias) {
+CPDF_Font* CBA_FontMap::GetAnnotDefaultFont(ByteString* sAlias) {
   CPDF_Dictionary* pAcroFormDict = nullptr;
   const bool bWidget = (m_pAnnotDict->GetStringFor("Subtype") == "Widget");
   if (bWidget) {
@@ -203,7 +202,7 @@
       pAcroFormDict = pRootDict->GetDictFor("AcroForm");
   }
 
-  CFX_ByteString sDA;
+  ByteString sDA;
   CPDF_Object* pObj = FPDF_GetFieldAttr(m_pAnnotDict.Get(), "DA");
   if (pObj)
     sDA = pObj->GetString();
@@ -211,17 +210,17 @@
   if (bWidget) {
     if (sDA.IsEmpty()) {
       pObj = FPDF_GetFieldAttr(pAcroFormDict, "DA");
-      sDA = pObj ? pObj->GetString() : CFX_ByteString();
+      sDA = pObj ? pObj->GetString() : ByteString();
     }
   }
   if (sDA.IsEmpty())
     return nullptr;
 
-  CPDF_SimpleParser syntax(sDA.AsStringC());
+  CPDF_SimpleParser syntax(sDA.AsStringView());
   syntax.FindTagParamFromStart("Tf", 2);
 
-  CFX_ByteString sFontName(syntax.GetWord());
-  CFX_ByteString sDecodedFontName = PDF_NameDecode(sFontName);
+  ByteString sFontName(syntax.GetWord());
+  ByteString sDecodedFontName = PDF_NameDecode(sFontName);
   *sAlias = sDecodedFontName.Right(sDecodedFontName.GetLength() - 1);
 
   CPDF_Dictionary* pFontDict = nullptr;
@@ -243,7 +242,7 @@
   return pFontDict ? m_pDocument->LoadFont(pFontDict) : nullptr;
 }
 
-void CBA_FontMap::SetAPType(const CFX_ByteString& sAPType) {
+void CBA_FontMap::SetAPType(const ByteString& sAPType) {
   m_sAPType = sAPType;
 
   Reset();
diff --git a/fpdfsdk/formfiller/cba_fontmap.h b/fpdfsdk/formfiller/cba_fontmap.h
index 7eb7d4e..807cb65 100644
--- a/fpdfsdk/formfiller/cba_fontmap.h
+++ b/fpdfsdk/formfiller/cba_fontmap.h
@@ -19,28 +19,28 @@
   ~CBA_FontMap() override;
 
   void Reset();
-  void SetDefaultFont(CPDF_Font* pFont, const CFX_ByteString& sFontName);
-  void SetAPType(const CFX_ByteString& sAPType);
+  void SetDefaultFont(CPDF_Font* pFont, const ByteString& sFontName);
+  void SetAPType(const ByteString& sAPType);
 
  private:
   // CPWL_FontMap:
   void Initialize() override;
   CPDF_Document* GetDocument() override;
-  CPDF_Font* FindFontSameCharset(CFX_ByteString* sFontAlias,
+  CPDF_Font* FindFontSameCharset(ByteString* sFontAlias,
                                  int32_t nCharset) override;
-  void AddedFont(CPDF_Font* pFont, const CFX_ByteString& sFontAlias) override;
+  void AddedFont(CPDF_Font* pFont, const ByteString& sFontAlias) override;
 
   CPDF_Font* FindResFontSameCharset(CPDF_Dictionary* pResDict,
-                                    CFX_ByteString* sFontAlias,
+                                    ByteString* sFontAlias,
                                     int32_t nCharset);
-  CPDF_Font* GetAnnotDefaultFont(CFX_ByteString* csNameTag);
-  void AddFontToAnnotDict(CPDF_Font* pFont, const CFX_ByteString& sAlias);
+  CPDF_Font* GetAnnotDefaultFont(ByteString* csNameTag);
+  void AddFontToAnnotDict(CPDF_Font* pFont, const ByteString& sAlias);
 
   CFX_UnownedPtr<CPDF_Document> m_pDocument;
   CFX_UnownedPtr<CPDF_Dictionary> m_pAnnotDict;
   CFX_UnownedPtr<CPDF_Font> m_pDefaultFont;
-  CFX_ByteString m_sDefaultFontName;
-  CFX_ByteString m_sAPType;
+  ByteString m_sDefaultFontName;
+  ByteString m_sAPType;
 };
 
 #endif  // FPDFSDK_FORMFILLER_CBA_FONTMAP_H_
diff --git a/fpdfsdk/formfiller/cffl_combobox.cpp b/fpdfsdk/formfiller/cffl_combobox.cpp
index aeb31f5..ab34a65 100644
--- a/fpdfsdk/formfiller/cffl_combobox.cpp
+++ b/fpdfsdk/formfiller/cffl_combobox.cpp
@@ -52,7 +52,7 @@
   pWnd->SetFillerNotify(pFormFiller);
 
   int32_t nCurSel = m_pWidget->GetSelectedIndex(0);
-  CFX_WideString swText;
+  WideString swText;
   if (nCurSel < 0)
     swText = m_pWidget->GetValue();
   else
@@ -94,7 +94,7 @@
   if (!pWnd)
     return;
 
-  CFX_WideString swText = pWnd->GetText();
+  WideString swText = pWnd->GetText();
   int32_t nCurSel = pWnd->GetSelect();
 
   bool bSetValue = false;
@@ -235,15 +235,15 @@
   pEdit->SetCharSet(FX_CHARSET_ChineseSimplified);
   pEdit->SetReadyToInput();
 
-  CFX_WideString wsText = pEdit->GetText();
+  WideString wsText = pEdit->GetText();
   int nCharacters = wsText.GetLength();
-  CFX_ByteString bsUTFText = wsText.UTF16LE_Encode();
+  ByteString bsUTFText = wsText.UTF16LE_Encode();
   auto* pBuffer = reinterpret_cast<const unsigned short*>(bsUTFText.c_str());
   m_pFormFillEnv->OnSetFieldInputFocus(pBuffer, nCharacters, true);
 }
 
-CFX_WideString CFFL_ComboBox::GetSelectExportText() {
-  CFX_WideString swRet;
+WideString CFFL_ComboBox::GetSelectExportText() {
+  WideString swRet;
 
   int nExport = -1;
   CPDFSDK_PageView* pPageView = GetCurPageView(true);
diff --git a/fpdfsdk/formfiller/cffl_combobox.h b/fpdfsdk/formfiller/cffl_combobox.h
index dc8441d..bdc0934 100644
--- a/fpdfsdk/formfiller/cffl_combobox.h
+++ b/fpdfsdk/formfiller/cffl_combobox.h
@@ -16,7 +16,7 @@
   int nIndex;
   int nStart;
   int nEnd;
-  CFX_WideString sValue;
+  WideString sValue;
 };
 
 class CFFL_ComboBox : public CFFL_TextObject,
@@ -50,7 +50,7 @@
   void OnSetFocus(CPWL_Edit* pEdit) override;
 
  private:
-  CFX_WideString GetSelectExportText();
+  WideString GetSelectExportText();
 
   FFL_ComboBoxState m_State;
 };
diff --git a/fpdfsdk/formfiller/cffl_formfiller.cpp b/fpdfsdk/formfiller/cffl_formfiller.cpp
index fd569c7..2c6138b 100644
--- a/fpdfsdk/formfiller/cffl_formfiller.cpp
+++ b/fpdfsdk/formfiller/cffl_formfiller.cpp
@@ -233,19 +233,19 @@
   return pWnd && pWnd->OnChar(nChar, nFlags);
 }
 
-CFX_WideString CFFL_FormFiller::GetSelectedText(CPDFSDK_Annot* pAnnot) {
+WideString CFFL_FormFiller::GetSelectedText(CPDFSDK_Annot* pAnnot) {
   if (!IsValid())
-    return CFX_WideString();
+    return WideString();
 
   CPDFSDK_PageView* pPageView = GetCurPageView(true);
   ASSERT(pPageView);
 
   CPWL_Wnd* pWnd = GetPDFWindow(pPageView, false);
-  return pWnd ? pWnd->GetSelectedText() : CFX_WideString();
+  return pWnd ? pWnd->GetSelectedText() : WideString();
 }
 
 void CFFL_FormFiller::ReplaceSelection(CPDFSDK_Annot* pAnnot,
-                                       const CFX_WideString& text) {
+                                       const WideString& text) {
   if (!IsValid())
     return;
 
diff --git a/fpdfsdk/formfiller/cffl_formfiller.h b/fpdfsdk/formfiller/cffl_formfiller.h
index e9c2c55..8078d35 100644
--- a/fpdfsdk/formfiller/cffl_formfiller.h
+++ b/fpdfsdk/formfiller/cffl_formfiller.h
@@ -75,8 +75,8 @@
                          uint32_t nFlags);
   virtual bool OnChar(CPDFSDK_Annot* pAnnot, uint32_t nChar, uint32_t nFlags);
 
-  CFX_WideString GetSelectedText(CPDFSDK_Annot* pAnnot);
-  void ReplaceSelection(CPDFSDK_Annot* pAnnot, const CFX_WideString& text);
+  WideString GetSelectedText(CPDFSDK_Annot* pAnnot);
+  void ReplaceSelection(CPDFSDK_Annot* pAnnot, const WideString& text);
 
   void SetFocusForAnnot(CPDFSDK_Annot* pAnnot, uint32_t nFlag);
   void KillFocusForAnnot(CPDFSDK_Annot* pAnnot, uint32_t nFlag);
diff --git a/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp b/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp
index 989539f..3625e9d 100644
--- a/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp
+++ b/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp
@@ -516,15 +516,14 @@
     UnRegisterFormFiller(pAnnot);
 }
 
-CFX_WideString CFFL_InteractiveFormFiller::GetSelectedText(
-    CPDFSDK_Annot* pAnnot) {
+WideString CFFL_InteractiveFormFiller::GetSelectedText(CPDFSDK_Annot* pAnnot) {
   ASSERT(pAnnot->GetPDFAnnot()->GetSubtype() == CPDF_Annot::Subtype::WIDGET);
   CFFL_FormFiller* pFormFiller = GetFormFiller(pAnnot, false);
-  return pFormFiller ? pFormFiller->GetSelectedText(pAnnot) : CFX_WideString();
+  return pFormFiller ? pFormFiller->GetSelectedText(pAnnot) : WideString();
 }
 
 void CFFL_InteractiveFormFiller::ReplaceSelection(CPDFSDK_Annot* pAnnot,
-                                                  const CFX_WideString& text) {
+                                                  const WideString& text) {
   ASSERT(pAnnot->GetPDFAnnot()->GetSubtype() == CPDF_Annot::Subtype::WIDGET);
   CFFL_FormFiller* pFormFiller = GetFormFiller(pAnnot, false);
   if (!pFormFiller)
@@ -690,8 +689,7 @@
   CPDFSDK_InterForm* pInterForm = pPageView->GetFormFillEnv()->GetInterForm();
 
   bool bFormatted = false;
-  CFX_WideString sValue =
-      pInterForm->OnFormat(pWidget->GetFormField(), bFormatted);
+  WideString sValue = pInterForm->OnFormat(pWidget->GetFormField(), bFormatted);
   if (!(*pAnnot))
     return;
 
@@ -857,8 +855,8 @@
 
 std::pair<bool, bool> CFFL_InteractiveFormFiller::OnBeforeKeyStroke(
     CPWL_Wnd::PrivateData* pAttached,
-    CFX_WideString& strChange,
-    const CFX_WideString& strChangeEx,
+    WideString& strChange,
+    const WideString& strChangeEx,
     int nSelStart,
     int nSelEnd,
     bool bKeyDown,
diff --git a/fpdfsdk/formfiller/cffl_interactiveformfiller.h b/fpdfsdk/formfiller/cffl_interactiveformfiller.h
index 0982f1d..553cbe8 100644
--- a/fpdfsdk/formfiller/cffl_interactiveformfiller.h
+++ b/fpdfsdk/formfiller/cffl_interactiveformfiller.h
@@ -83,8 +83,8 @@
   CFFL_FormFiller* GetFormFiller(CPDFSDK_Annot* pAnnot, bool bRegister);
   void RemoveFormFiller(CPDFSDK_Annot* pAnnot);
 
-  CFX_WideString GetSelectedText(CPDFSDK_Annot* pAnnot);
-  void ReplaceSelection(CPDFSDK_Annot* pAnnot, const CFX_WideString& text);
+  WideString GetSelectedText(CPDFSDK_Annot* pAnnot);
+  void ReplaceSelection(CPDFSDK_Annot* pAnnot, const WideString& text);
 
   static bool IsVisible(CPDFSDK_Widget* pWidget);
   static bool IsReadOnly(CPDFSDK_Widget* pWidget);
@@ -133,8 +133,8 @@
                        float* fPopupRet) override;
   // Returns {bRC, bExit}.
   std::pair<bool, bool> OnBeforeKeyStroke(CPWL_Wnd::PrivateData* pAttached,
-                                          CFX_WideString& strChange,
-                                          const CFX_WideString& strChangeEx,
+                                          WideString& strChange,
+                                          const WideString& strChangeEx,
                                           int nSelStart,
                                           int nSelEnd,
                                           bool bKeyDown,
diff --git a/fpdfsdk/formfiller/cffl_textfield.cpp b/fpdfsdk/formfiller/cffl_textfield.cpp
index 8bf0825..76434a5 100644
--- a/fpdfsdk/formfiller/cffl_textfield.cpp
+++ b/fpdfsdk/formfiller/cffl_textfield.cpp
@@ -74,7 +74,7 @@
   pWnd->SetFillerNotify(m_pFormFillEnv->GetInteractiveFormFiller());
 
   int32_t nMaxLen = m_pWidget->GetMaxLen();
-  CFX_WideString swValue = m_pWidget->GetValue();
+  WideString swValue = m_pWidget->GetValue();
 
   if (nMaxLen > 0) {
     if (pWnd->HasFlag(PES_CHARARRAY)) {
@@ -136,8 +136,8 @@
   if (!pWnd)
     return;
 
-  CFX_WideString sOldValue = m_pWidget->GetValue();
-  CFX_WideString sNewValue = pWnd->GetText();
+  WideString sOldValue = m_pWidget->GetValue();
+  WideString sNewValue = pWnd->GetText();
 
   m_pWidget->SetValue(sNewValue, false);
   m_pWidget->ResetFieldAppearance(true);
@@ -239,9 +239,9 @@
   pEdit->SetCharSet(FX_CHARSET_ChineseSimplified);
   pEdit->SetReadyToInput();
 
-  CFX_WideString wsText = pEdit->GetText();
+  WideString wsText = pEdit->GetText();
   int nCharacters = wsText.GetLength();
-  CFX_ByteString bsUTFText = wsText.UTF16LE_Encode();
+  ByteString bsUTFText = wsText.UTF16LE_Encode();
   auto* pBuffer = reinterpret_cast<const unsigned short*>(bsUTFText.c_str());
   m_pFormFillEnv->OnSetFieldInputFocus(pBuffer, nCharacters, true);
 }
diff --git a/fpdfsdk/formfiller/cffl_textfield.h b/fpdfsdk/formfiller/cffl_textfield.h
index 2a99413..49ffc0f 100644
--- a/fpdfsdk/formfiller/cffl_textfield.h
+++ b/fpdfsdk/formfiller/cffl_textfield.h
@@ -21,7 +21,7 @@
 
   int nStart;
   int nEnd;
-  CFX_WideString sValue;
+  WideString sValue;
 };
 
 class CFFL_TextField : public CFFL_TextObject,