diff --git a/fxjs/cfx_globaldata.cpp b/fxjs/cfx_globaldata.cpp
index 26e30bf..cc1084f 100644
--- a/fxjs/cfx_globaldata.cpp
+++ b/fxjs/cfx_globaldata.cpp
@@ -257,7 +257,7 @@
   bool ret;
   {
     // Span can't outlive call to BufferDone().
-    Optional<pdfium::span<uint8_t>> buffer = m_pDelegate->LoadBuffer();
+    absl::optional<pdfium::span<uint8_t>> buffer = m_pDelegate->LoadBuffer();
     if (!buffer.has_value() || buffer.value().empty())
       return false;
 
diff --git a/fxjs/cfx_globaldata.h b/fxjs/cfx_globaldata.h
index 5d260c7..40e5548 100644
--- a/fxjs/cfx_globaldata.h
+++ b/fxjs/cfx_globaldata.h
@@ -23,7 +23,7 @@
     virtual ~Delegate() = default;
 
     virtual bool StoreBuffer(pdfium::span<const uint8_t> pBuffer) = 0;
-    virtual Optional<pdfium::span<uint8_t>> LoadBuffer() = 0;
+    virtual absl::optional<pdfium::span<uint8_t>> LoadBuffer() = 0;
     virtual void BufferDone() = 0;
   };
 
diff --git a/fxjs/cfx_globaldata_unittest.cpp b/fxjs/cfx_globaldata_unittest.cpp
index 24c080a..99dbccf 100644
--- a/fxjs/cfx_globaldata_unittest.cpp
+++ b/fxjs/cfx_globaldata_unittest.cpp
@@ -21,7 +21,7 @@
         buffer.begin(), buffer.end());
     return true;
   }
-  Optional<pdfium::span<uint8_t>> LoadBuffer() override {
+  absl::optional<pdfium::span<uint8_t>> LoadBuffer() override {
     return pdfium::span<uint8_t>(last_buffer_);
   }
   void BufferDone() override {
diff --git a/fxjs/cfxjs_engine.cpp b/fxjs/cfxjs_engine.cpp
index af68a2e..9f15613 100644
--- a/fxjs/cfxjs_engine.cpp
+++ b/fxjs/cfxjs_engine.cpp
@@ -562,7 +562,7 @@
   GetIsolate()->SetData(g_embedderDataSlot, nullptr);
 }
 
-Optional<IJS_Runtime::JS_Error> CFXJS_Engine::Execute(
+absl::optional<IJS_Runtime::JS_Error> CFXJS_Engine::Execute(
     const WideString& script) {
   v8::Isolate::Scope isolate_scope(GetIsolate());
   v8::TryCatch try_catch(GetIsolate());
diff --git a/fxjs/cfxjs_engine.h b/fxjs/cfxjs_engine.h
index 4f1c08e..45dc664 100644
--- a/fxjs/cfxjs_engine.h
+++ b/fxjs/cfxjs_engine.h
@@ -120,7 +120,7 @@
   void ReleaseEngine();
 
   // Called after FXJS_InitializeEngine call made.
-  Optional<IJS_Runtime::JS_Error> Execute(const WideString& script);
+  absl::optional<IJS_Runtime::JS_Error> Execute(const WideString& script);
 
   v8::Local<v8::Object> GetThisObj();
   v8::Local<v8::Object> NewFXJSBoundObject(uint32_t nObjDefnID,
diff --git a/fxjs/cfxjs_engine_embeddertest.cpp b/fxjs/cfxjs_engine_embeddertest.cpp
index abeb64d..5763f4d 100644
--- a/fxjs/cfxjs_engine_embeddertest.cpp
+++ b/fxjs/cfxjs_engine_embeddertest.cpp
@@ -35,7 +35,8 @@
   v8::HandleScope handle_scope(isolate());
   v8::Context::Scope context_scope(GetV8Context());
 
-  Optional<IJS_Runtime::JS_Error> err = engine()->Execute(WideString(kScript1));
+  absl::optional<IJS_Runtime::JS_Error> err =
+      engine()->Execute(WideString(kScript1));
   EXPECT_FALSE(err);
   CheckAssignmentInEngineContext(engine(), kExpected1);
 }
@@ -52,7 +53,7 @@
 
   v8::Context::Scope context_scope(GetV8Context());
   {
-    Optional<IJS_Runtime::JS_Error> err =
+    absl::optional<IJS_Runtime::JS_Error> err =
         engine()->Execute(WideString(kScript0));
     EXPECT_FALSE(err);
     CheckAssignmentInEngineContext(engine(), kExpected0);
@@ -60,7 +61,8 @@
   {
     // engine1 executing in engine1's context doesn't affect main.
     v8::Context::Scope context_scope1(engine1.GetV8Context());
-    Optional<IJS_Runtime::JS_Error> err = engine1.Execute(WideString(kScript1));
+    absl::optional<IJS_Runtime::JS_Error> err =
+        engine1.Execute(WideString(kScript1));
     EXPECT_FALSE(err);
     CheckAssignmentInEngineContext(engine(), kExpected0);
     CheckAssignmentInEngineContext(&engine1, kExpected1);
@@ -68,7 +70,8 @@
   {
     // engine1 executing in engine2's context doesn't affect engine1.
     v8::Context::Scope context_scope2(engine2.GetV8Context());
-    Optional<IJS_Runtime::JS_Error> err = engine1.Execute(WideString(kScript2));
+    absl::optional<IJS_Runtime::JS_Error> err =
+        engine1.Execute(WideString(kScript2));
     EXPECT_FALSE(err);
     CheckAssignmentInEngineContext(engine(), kExpected0);
     CheckAssignmentInEngineContext(&engine1, kExpected1);
@@ -83,7 +86,7 @@
   v8::HandleScope handle_scope(isolate());
   v8::Context::Scope context_scope(GetV8Context());
 
-  Optional<IJS_Runtime::JS_Error> err =
+  absl::optional<IJS_Runtime::JS_Error> err =
       engine()->Execute(L"functoon(x) { return x+1; }");
   EXPECT_TRUE(err);
   EXPECT_STREQ(L"SyntaxError: Unexpected token '{'", err->exception.c_str());
@@ -96,7 +99,7 @@
   v8::HandleScope handle_scope(isolate());
   v8::Context::Scope context_scope(GetV8Context());
 
-  Optional<IJS_Runtime::JS_Error> err =
+  absl::optional<IJS_Runtime::JS_Error> err =
       engine()->Execute(L"let a = 3;\nundefined.colour");
   EXPECT_TRUE(err);
   EXPECT_EQ(
diff --git a/fxjs/cfxjs_engine_unittest.cpp b/fxjs/cfxjs_engine_unittest.cpp
index 0470a78..496aead 100644
--- a/fxjs/cfxjs_engine_unittest.cpp
+++ b/fxjs/cfxjs_engine_unittest.cpp
@@ -84,7 +84,7 @@
     EXPECT_FALSE(temp_destroyed);
   }
 
-  Optional<IJS_Runtime::JS_Error> err = engine()->Execute(L"gc();");
+  absl::optional<IJS_Runtime::JS_Error> err = engine()->Execute(L"gc();");
   EXPECT_FALSE(err);
 
   EXPECT_TRUE(perm_created);
diff --git a/fxjs/cjs_event_context.cpp b/fxjs/cjs_event_context.cpp
index da8b8ee..888d429 100644
--- a/fxjs/cjs_event_context.cpp
+++ b/fxjs/cjs_event_context.cpp
@@ -22,7 +22,7 @@
 
 CJS_EventContext::~CJS_EventContext() = default;
 
-Optional<IJS_Runtime::JS_Error> CJS_EventContext::RunScript(
+absl::optional<IJS_Runtime::JS_Error> CJS_EventContext::RunScript(
     const WideString& script) {
   v8::Isolate::Scope isolate_scope(m_pRuntime->GetIsolate());
   v8::HandleScope handle_scope(m_pRuntime->GetIsolate());
@@ -44,7 +44,7 @@
         1, 1, JSGetStringFromID(JSMessage::kDuplicateEventError));
   }
 
-  Optional<IJS_Runtime::JS_Error> err;
+  absl::optional<IJS_Runtime::JS_Error> err;
   if (script.GetLength() > 0)
     err = m_pRuntime->ExecuteScript(script);
 
diff --git a/fxjs/cjs_event_context.h b/fxjs/cjs_event_context.h
index b911fc2..6c07e44 100644
--- a/fxjs/cjs_event_context.h
+++ b/fxjs/cjs_event_context.h
@@ -47,7 +47,8 @@
   ~CJS_EventContext() override;
 
   // IJS_EventContext
-  Optional<IJS_Runtime::JS_Error> RunScript(const WideString& script) override;
+  absl::optional<IJS_Runtime::JS_Error> RunScript(
+      const WideString& script) override;
   void OnDoc_Open(const WideString& strTargetName) override;
   void OnDoc_WillPrint() override;
   void OnDoc_DidPrint() override;
diff --git a/fxjs/cjs_event_context_stub.cpp b/fxjs/cjs_event_context_stub.cpp
index d19c6eb..e5b6f30 100644
--- a/fxjs/cjs_event_context_stub.cpp
+++ b/fxjs/cjs_event_context_stub.cpp
@@ -10,7 +10,7 @@
 
 CJS_EventContextStub::~CJS_EventContextStub() = default;
 
-Optional<IJS_Runtime::JS_Error> CJS_EventContextStub::RunScript(
+absl::optional<IJS_Runtime::JS_Error> CJS_EventContextStub::RunScript(
     const WideString& script) {
   return IJS_Runtime::JS_Error(1, 1, L"JavaScript support not present");
 }
diff --git a/fxjs/cjs_event_context_stub.h b/fxjs/cjs_event_context_stub.h
index 44d4a85..72d9613 100644
--- a/fxjs/cjs_event_context_stub.h
+++ b/fxjs/cjs_event_context_stub.h
@@ -15,7 +15,8 @@
   ~CJS_EventContextStub() override;
 
   // IJS_EventContext:
-  Optional<IJS_Runtime::JS_Error> RunScript(const WideString& script) override;
+  absl::optional<IJS_Runtime::JS_Error> RunScript(
+      const WideString& script) override;
 
   void OnDoc_Open(const WideString& strTargetName) override {}
   void OnDoc_WillPrint() override {}
diff --git a/fxjs/cjs_field.cpp b/fxjs/cjs_field.cpp
index a2974e4..ba447b1 100644
--- a/fxjs/cjs_field.cpp
+++ b/fxjs/cjs_field.cpp
@@ -63,7 +63,7 @@
     if (IsComboBoxOrTextField(pFormField)) {
       for (auto& pObserved : widgets) {
         if (pObserved) {
-          Optional<WideString> sValue =
+          absl::optional<WideString> sValue =
               ToCPDFSDKWidget(pObserved.Get())->OnFormat();
           if (pObserved) {  // Not redundant, may be clobbered by OnFormat.
             auto* pWidget = ToCPDFSDKWidget(pObserved.Get());
@@ -121,7 +121,7 @@
       FormFieldType fieldType = pWidget->GetFieldType();
       if (fieldType == FormFieldType::kComboBox ||
           fieldType == FormFieldType::kTextField) {
-        Optional<WideString> sValue = pWidget->OnFormat();
+        absl::optional<WideString> sValue = pWidget->OnFormat();
         if (!observed_widget)
           return;
         pWidget->ResetAppearance(sValue, CPDFSDK_Widget::kValueUnchanged);
@@ -151,7 +151,7 @@
   int control_index;
 };
 
-Optional<FieldNameData> ParseFieldName(const WideString& field_name) {
+absl::optional<FieldNameData> ParseFieldName(const WideString& field_name) {
   auto reverse_it = field_name.rbegin();
   while (reverse_it != field_name.rend()) {
     if (*reverse_it == L'.')
@@ -655,7 +655,7 @@
   swFieldNameTemp.Replace(L"..", L".");
 
   if (pForm->CountFields(swFieldNameTemp) <= 0) {
-    Optional<FieldNameData> parsed_data = ParseFieldName(swFieldNameTemp);
+    absl::optional<FieldNameData> parsed_data = ParseFieldName(swFieldNameTemp);
     if (!parsed_data.has_value())
       return false;
 
@@ -1918,7 +1918,7 @@
     return CJS_Result::Failure(JSMessage::kBadObjectError);
 
   CPDF_DefaultAppearance FieldAppearance = pFormControl->GetDefaultAppearance();
-  Optional<CFX_Color::TypeAndARGB> maybe_type_argb_pair =
+  absl::optional<CFX_Color::TypeAndARGB> maybe_type_argb_pair =
       FieldAppearance.GetColorARGB();
 
   CFX_Color crRet;
@@ -1969,7 +1969,8 @@
     return CJS_Result::Failure(JSMessage::kObjectTypeError);
   }
 
-  Optional<WideString> wsFontName = pFormControl->GetDefaultControlFontName();
+  absl::optional<WideString> wsFontName =
+      pFormControl->GetDefaultControlFontName();
   if (!wsFontName.has_value())
     return CJS_Result::Failure(JSMessage::kBadObjectError);
 
diff --git a/fxjs/cjs_publicmethods.cpp b/fxjs/cjs_publicmethods.cpp
index dc481c4..beb1bde 100644
--- a/fxjs/cjs_publicmethods.cpp
+++ b/fxjs/cjs_publicmethods.cpp
@@ -209,9 +209,9 @@
   str->Replace(L",", L".");
 }
 
-Optional<double> ApplyNamedOperation(const wchar_t* sFunction,
-                                     double dValue1,
-                                     double dValue2) {
+absl::optional<double> ApplyNamedOperation(const wchar_t* sFunction,
+                                           double dValue1,
+                                           double dValue2) {
   if (FXSYS_wcsicmp(sFunction, L"AVG") == 0 ||
       FXSYS_wcsicmp(sFunction, L"SUM") == 0) {
     return dValue1 + dValue2;
@@ -840,7 +840,7 @@
   strValue.ReleaseBuffer(szNewSize);
 
   // for processing separator style
-  Optional<size_t> mark_pos = strValue.Find('.');
+  absl::optional<size_t> mark_pos = strValue.Find('.');
   if (mark_pos.has_value()) {
     char mark = DecimalMarkForStyle(iSepStyle);
     if (mark != '.')
@@ -1245,7 +1245,8 @@
   if (isnan(arg1) || isnan(arg2))
     return CJS_Result::Failure(JSMessage::kValueError);
 
-  Optional<double> result = ApplyNamedOperation(sFunction.c_str(), arg1, arg2);
+  absl::optional<double> result =
+      ApplyNamedOperation(sFunction.c_str(), arg1, arg2);
   if (!result.has_value())
     return CJS_Result::Failure(JSMessage::kValueError);
 
@@ -1344,7 +1345,7 @@
            wcscmp(sFunction.c_str(), L"MAX") == 0)) {
         dValue = dTemp;
       }
-      Optional<double> dResult =
+      absl::optional<double> dResult =
           ApplyNamedOperation(sFunction.c_str(), dValue, dTemp);
       if (!dResult.has_value())
         return CJS_Result::Failure(JSMessage::kValueError);
diff --git a/fxjs/cjs_result.h b/fxjs/cjs_result.h
index f639842..1f1a215 100644
--- a/fxjs/cjs_result.h
+++ b/fxjs/cjs_result.h
@@ -50,7 +50,7 @@
   explicit CJS_Result(const WideString&);     // Error with custom message.
   explicit CJS_Result(JSMessage id);          // Error with stock message.
 
-  Optional<WideString> error_;
+  absl::optional<WideString> error_;
   v8::Local<v8::Value> return_;
 };
 
diff --git a/fxjs/cjs_runtime.cpp b/fxjs/cjs_runtime.cpp
index d73744c..91d2499 100644
--- a/fxjs/cjs_runtime.cpp
+++ b/fxjs/cjs_runtime.cpp
@@ -166,7 +166,7 @@
   return m_pFormFillEnv.Get();
 }
 
-Optional<IJS_Runtime::JS_Error> CJS_Runtime::ExecuteScript(
+absl::optional<IJS_Runtime::JS_Error> CJS_Runtime::ExecuteScript(
     const WideString& script) {
   return Execute(script);
 }
diff --git a/fxjs/cjs_runtime.h b/fxjs/cjs_runtime.h
index d95cb26..d36fe9f 100644
--- a/fxjs/cjs_runtime.h
+++ b/fxjs/cjs_runtime.h
@@ -34,7 +34,7 @@
   IJS_EventContext* NewEventContext() override;
   void ReleaseEventContext(IJS_EventContext* pContext) override;
   CPDFSDK_FormFillEnvironment* GetFormFillEnv() const override;
-  Optional<IJS_Runtime::JS_Error> ExecuteScript(
+  absl::optional<IJS_Runtime::JS_Error> ExecuteScript(
       const WideString& script) override;
 
   CJS_EventContext* GetCurrentEventContext() const;
diff --git a/fxjs/cjs_runtimestub.cpp b/fxjs/cjs_runtimestub.cpp
index 39600fa..5ba2b9f 100644
--- a/fxjs/cjs_runtimestub.cpp
+++ b/fxjs/cjs_runtimestub.cpp
@@ -29,7 +29,7 @@
   return nullptr;
 }
 
-Optional<IJS_Runtime::JS_Error> CJS_RuntimeStub::ExecuteScript(
+absl::optional<IJS_Runtime::JS_Error> CJS_RuntimeStub::ExecuteScript(
     const WideString& script) {
   return absl::nullopt;
 }
diff --git a/fxjs/cjs_runtimestub.h b/fxjs/cjs_runtimestub.h
index 2b5e713..eda8a87 100644
--- a/fxjs/cjs_runtimestub.h
+++ b/fxjs/cjs_runtimestub.h
@@ -27,7 +27,7 @@
   void ReleaseEventContext(IJS_EventContext* pContext) override;
   CPDFSDK_FormFillEnvironment* GetFormFillEnv() const override;
 
-  Optional<IJS_Runtime::JS_Error> ExecuteScript(
+  absl::optional<IJS_Runtime::JS_Error> ExecuteScript(
       const WideString& script) override;
 
  private:
diff --git a/fxjs/cjs_util.cpp b/fxjs/cjs_util.cpp
index 8a346d1..0a27b57 100644
--- a/fxjs/cjs_util.cpp
+++ b/fxjs/cjs_util.cpp
@@ -112,7 +112,8 @@
   {
     size_t offset = 0;
     while (true) {
-      Optional<size_t> offset_end = unsafe_fmt_string.Find(L"%", offset + 1);
+      absl::optional<size_t> offset_end =
+          unsafe_fmt_string.Find(L"%", offset + 1);
       if (!offset_end.has_value()) {
         unsafe_conversion_specifiers.push_back(
             unsafe_fmt_string.Last(unsafe_fmt_string.GetLength() - offset));
diff --git a/fxjs/ijs_event_context.h b/fxjs/ijs_event_context.h
index f142ebc..7f4d7f3 100644
--- a/fxjs/ijs_event_context.h
+++ b/fxjs/ijs_event_context.h
@@ -20,7 +20,7 @@
  public:
   virtual ~IJS_EventContext() = default;
 
-  virtual Optional<IJS_Runtime::JS_Error> RunScript(
+  virtual absl::optional<IJS_Runtime::JS_Error> RunScript(
       const WideString& script) = 0;
 
   virtual void OnDoc_Open(const WideString& strTargetName) = 0;
diff --git a/fxjs/ijs_runtime.h b/fxjs/ijs_runtime.h
index 4ce4acd..ed9b701 100644
--- a/fxjs/ijs_runtime.h
+++ b/fxjs/ijs_runtime.h
@@ -57,7 +57,7 @@
   virtual IJS_EventContext* NewEventContext() = 0;
   virtual void ReleaseEventContext(IJS_EventContext* pContext) = 0;
   virtual CPDFSDK_FormFillEnvironment* GetFormFillEnv() const = 0;
-  virtual Optional<JS_Error> ExecuteScript(const WideString& script) = 0;
+  virtual absl::optional<JS_Error> ExecuteScript(const WideString& script) = 0;
 
  protected:
   IJS_Runtime() = default;
diff --git a/fxjs/xfa/cfxjse_engine.cpp b/fxjs/xfa/cfxjse_engine.cpp
index 42c95da..82594ca 100644
--- a/fxjs/xfa/cfxjse_engine.cpp
+++ b/fxjs/xfa/cfxjse_engine.cpp
@@ -161,7 +161,7 @@
       m_FM2JSContext = std::make_unique<CFXJSE_FormCalcContext>(
           GetIsolate(), m_JsContext.get(), m_pDocument.Get());
     }
-    Optional<CFX_WideTextBuf> wsJavaScript =
+    absl::optional<CFX_WideTextBuf> wsJavaScript =
         CFXJSE_FormCalcContext::Translate(m_pDocument->GetHeap(), wsScript);
     if (!wsJavaScript.has_value()) {
       hRetValue->SetUndefined(GetIsolate());
@@ -189,7 +189,7 @@
   if (!refNode)
     return false;
 
-  Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+  absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
       ResolveObjects(refNode, propname, dwFlag);
   if (!maybeResult.has_value())
     return false;
@@ -216,7 +216,7 @@
   if (!refNode)
     return false;
 
-  Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+  absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
       ResolveObjects(refNode, propname, dwFlag);
   if (!maybeResult.has_value())
     return false;
@@ -404,7 +404,7 @@
                                          &pReturnValue)) {
     return pReturnValue;
   }
-  Optional<XFA_SCRIPTATTRIBUTEINFO> info = XFA_GetScriptAttributeByName(
+  absl::optional<XFA_SCRIPTATTRIBUTEINFO> info = XFA_GetScriptAttributeByName(
       pObject->GetElementType(), wsPropName.AsStringView());
   if (info.has_value()) {
     (*info.value().callback)(pIsolate, pObject->JSObject(), &pReturnValue,
@@ -442,7 +442,7 @@
   CXFA_Object* pObject = pScriptContext->GetVariablesThis(pOriginalObject);
   WideString wsPropName = WideString::FromUTF8(szPropName);
   WideStringView wsPropNameView = wsPropName.AsStringView();
-  Optional<XFA_SCRIPTATTRIBUTEINFO> info =
+  absl::optional<XFA_SCRIPTATTRIBUTEINFO> info =
       XFA_GetScriptAttributeByName(pObject->GetElementType(), wsPropNameView);
   if (info.has_value()) {
     CJX_Object* jsObject = pObject->JSObject();
@@ -501,7 +501,7 @@
     return FXJSE_ClassPropType::kMethod;
 
   if (bQueryIn) {
-    Optional<XFA_SCRIPTATTRIBUTEINFO> maybe_info =
+    absl::optional<XFA_SCRIPTATTRIBUTEINFO> maybe_info =
         XFA_GetScriptAttributeByName(eType, wsPropName.AsStringView());
     if (!maybe_info.has_value())
       return FXJSE_ClassPropType::kNone;
@@ -580,7 +580,7 @@
   if (!pTextNode)
     return false;
 
-  Optional<WideString> wsScript =
+  absl::optional<WideString> wsScript =
       pTextNode->JSObject()->TryCData(XFA_Attribute::Value, true);
   if (!wsScript.has_value())
     return false;
@@ -657,14 +657,14 @@
   fxv8::ReentrantDeleteObjectPropertyHelper(GetIsolate(), pObject, "Date");
 }
 
-Optional<CFXJSE_Engine::ResolveResult> CFXJSE_Engine::ResolveObjects(
+absl::optional<CFXJSE_Engine::ResolveResult> CFXJSE_Engine::ResolveObjects(
     CXFA_Object* refObject,
     WideStringView wsExpression,
     Mask<XFA_ResolveFlag> dwStyles) {
   return ResolveObjectsWithBindNode(refObject, wsExpression, dwStyles, nullptr);
 }
 
-Optional<CFXJSE_Engine::ResolveResult>
+absl::optional<CFXJSE_Engine::ResolveResult>
 CFXJSE_Engine::ResolveObjectsWithBindNode(CXFA_Object* refObject,
                                           WideStringView wsExpression,
                                           Mask<XFA_ResolveFlag> dwStyles,
diff --git a/fxjs/xfa/cfxjse_engine.h b/fxjs/xfa/cfxjse_engine.h
index d07c799..acbddf6 100644
--- a/fxjs/xfa/cfxjse_engine.h
+++ b/fxjs/xfa/cfxjse_engine.h
@@ -116,11 +116,11 @@
                  CFXJSE_Value* pRetValue,
                  CXFA_Object* pThisObject);
 
-  Optional<ResolveResult> ResolveObjects(CXFA_Object* refObject,
-                                         WideStringView wsExpression,
-                                         Mask<XFA_ResolveFlag> dwStyles);
+  absl::optional<ResolveResult> ResolveObjects(CXFA_Object* refObject,
+                                               WideStringView wsExpression,
+                                               Mask<XFA_ResolveFlag> dwStyles);
 
-  Optional<ResolveResult> ResolveObjectsWithBindNode(
+  absl::optional<ResolveResult> ResolveObjectsWithBindNode(
       CXFA_Object* refObject,
       WideStringView wsExpression,
       Mask<XFA_ResolveFlag> dwStyles,
diff --git a/fxjs/xfa/cfxjse_formcalc_context.cpp b/fxjs/xfa/cfxjse_formcalc_context.cpp
index e51d699..0569736 100644
--- a/fxjs/xfa/cfxjse_formcalc_context.cpp
+++ b/fxjs/xfa/cfxjse_formcalc_context.cpp
@@ -1447,8 +1447,8 @@
   return fxv8::ReentrantToDoubleHelper(pIsolate, extracted);
 }
 
-Optional<double> ExtractDouble(v8::Isolate* pIsolate,
-                               v8::Local<v8::Value> src) {
+absl::optional<double> ExtractDouble(v8::Isolate* pIsolate,
+                                     v8::Local<v8::Value> src) {
   if (src.IsEmpty())
     return 0.0;
 
@@ -1559,7 +1559,7 @@
     return v8::Local<v8::Value>();
 
   CFXJSE_Engine* pScriptContext = pDoc->GetScriptContext();
-  Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+  absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
       pScriptContext->ResolveObjects(
           pScriptContext->GetThisObject(),
           WideString::FromUTF8(bsAccessorName).AsStringView(),
@@ -1575,7 +1575,7 @@
       maybeResult.value().objects.front().Get());
 }
 
-Optional<CFXJSE_Engine::ResolveResult> ResolveObjects(
+absl::optional<CFXJSE_Engine::ResolveResult> ResolveObjects(
     CFXJSE_HostObject* pHostObject,
     v8::Local<v8::Value> pRefValue,
     ByteStringView bsSomExp,
@@ -1602,7 +1602,7 @@
       if (bHasNoResolveName) {
         WideString wsName;
         if (CXFA_Node* pXFANode = pNode->AsNode()) {
-          Optional<WideString> ret =
+          absl::optional<WideString> ret =
               pXFANode->JSObject()->TryAttribute(XFA_Attribute::Name, false);
           if (ret.has_value())
             wsName = ret.value();
@@ -1829,8 +1829,10 @@
     return;
   }
 
-  Optional<double> maybe_dividend = ExtractDouble(info.GetIsolate(), info[0]);
-  Optional<double> maybe_divisor = ExtractDouble(info.GetIsolate(), info[1]);
+  absl::optional<double> maybe_dividend =
+      ExtractDouble(info.GetIsolate(), info[0]);
+  absl::optional<double> maybe_divisor =
+      ExtractDouble(info.GetIsolate(), info[1]);
   if (!maybe_dividend.has_value() || !maybe_divisor.has_value()) {
     pContext->ThrowArgumentMismatchException();
     return;
@@ -1863,7 +1865,8 @@
     return;
   }
 
-  Optional<double> maybe_value = ExtractDouble(info.GetIsolate(), info[0]);
+  absl::optional<double> maybe_value =
+      ExtractDouble(info.GetIsolate(), info[0]);
   if (!maybe_value.has_value()) {
     pContext->ThrowArgumentMismatchException();
     return;
@@ -1876,7 +1879,7 @@
       info.GetReturnValue().SetNull();
       return;
     }
-    Optional<double> maybe_precision =
+    absl::optional<double> maybe_precision =
         ExtractDouble(info.GetIsolate(), info[1]);
     if (!maybe_precision.has_value()) {
       pContext->ThrowArgumentMismatchException();
@@ -3301,8 +3304,9 @@
   }
 
   WideString wsCalcScript = WideString::FromUTF8(bsUtf8Script.AsStringView());
-  Optional<CFX_WideTextBuf> wsJavaScriptBuf = CFXJSE_FormCalcContext::Translate(
-      pContext->GetDocument()->GetHeap(), wsCalcScript.AsStringView());
+  absl::optional<CFX_WideTextBuf> wsJavaScriptBuf =
+      CFXJSE_FormCalcContext::Translate(pContext->GetDocument()->GetHeap(),
+                                        wsCalcScript.AsStringView());
   if (!wsJavaScriptBuf.has_value()) {
     pContext->ThrowCompilerErrorException();
     return;
@@ -5110,8 +5114,9 @@
   }
 
   WideString wsCalcScript = WideString::FromUTF8(bsArg.AsStringView());
-  Optional<CFX_WideTextBuf> wsJavaScriptBuf = CFXJSE_FormCalcContext::Translate(
-      pContext->GetDocument()->GetHeap(), wsCalcScript.AsStringView());
+  absl::optional<CFX_WideTextBuf> wsJavaScriptBuf =
+      CFXJSE_FormCalcContext::Translate(pContext->GetDocument()->GetHeap(),
+                                        wsCalcScript.AsStringView());
   if (!wsJavaScriptBuf.has_value()) {
     pContext->ThrowCompilerErrorException();
     return;
@@ -5291,7 +5296,7 @@
   return bsSomExp;
 }
 
-Optional<CFX_WideTextBuf> CFXJSE_FormCalcContext::Translate(
+absl::optional<CFX_WideTextBuf> CFXJSE_FormCalcContext::Translate(
     cppgc::Heap* pHeap,
     WideStringView wsFormcalc) {
   if (wsFormcalc.IsEmpty())
@@ -5304,7 +5309,7 @@
     return absl::nullopt;
 
   CXFA_FMToJavaScriptDepth::Reset();
-  Optional<CFX_WideTextBuf> wsJavaScript = ast->ToJavaScript();
+  absl::optional<CFX_WideTextBuf> wsJavaScript = ast->ToJavaScript();
   if (!wsJavaScript.has_value())
     return absl::nullopt;
 
@@ -5379,7 +5384,7 @@
     for (uint32_t i = 2; i < iLength; i++) {
       v8::Local<v8::Value> hJSObjValue =
           fxv8::ReentrantGetArrayElementHelper(info.GetIsolate(), arr, i);
-      Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+      absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
           ResolveObjects(pThis, hJSObjValue, bsSomExp.AsStringView(),
                          bDotAccessor, bHasNoResolveName);
       if (maybeResult.has_value()) {
@@ -5409,7 +5414,7 @@
     return;
   }
 
-  Optional<CFXJSE_Engine::ResolveResult> maybeResult;
+  absl::optional<CFXJSE_Engine::ResolveResult> maybeResult;
   ByteString bsAccessorName =
       fxv8::ReentrantToByteStringHelper(info.GetIsolate(), info[1]);
   if (fxv8::IsObject(argAccessor) ||
diff --git a/fxjs/xfa/cfxjse_formcalc_context.h b/fxjs/xfa/cfxjse_formcalc_context.h
index ba79645..304359a 100644
--- a/fxjs/xfa/cfxjse_formcalc_context.h
+++ b/fxjs/xfa/cfxjse_formcalc_context.h
@@ -270,8 +270,8 @@
                                           int32_t iIndexFlags,
                                           int32_t iIndexValue,
                                           bool bIsStar);
-  static Optional<CFX_WideTextBuf> Translate(cppgc::Heap* pHeap,
-                                             WideStringView wsFormcalc);
+  static absl::optional<CFX_WideTextBuf> Translate(cppgc::Heap* pHeap,
+                                                   WideStringView wsFormcalc);
 
   v8::Local<v8::Value> GlobalPropertyGetter();
   v8::Isolate* GetIsolate() const { return m_pIsolate.Get(); }
diff --git a/fxjs/xfa/cfxjse_mapmodule.cpp b/fxjs/xfa/cfxjse_mapmodule.cpp
index e2344082..dbd6fed 100644
--- a/fxjs/xfa/cfxjse_mapmodule.cpp
+++ b/fxjs/xfa/cfxjse_mapmodule.cpp
@@ -32,21 +32,21 @@
   m_MeasurementMap[key] = measurement;
 }
 
-Optional<int32_t> CFXJSE_MapModule::GetValue(uint32_t key) const {
+absl::optional<int32_t> CFXJSE_MapModule::GetValue(uint32_t key) const {
   auto it = m_ValueMap.find(key);
   if (it == m_ValueMap.end())
     return absl::nullopt;
   return it->second;
 }
 
-Optional<WideString> CFXJSE_MapModule::GetString(uint32_t key) const {
+absl::optional<WideString> CFXJSE_MapModule::GetString(uint32_t key) const {
   auto it = m_StringMap.find(key);
   if (it == m_StringMap.end())
     return absl::nullopt;
   return it->second;
 }
 
-Optional<CXFA_Measurement> CFXJSE_MapModule::GetMeasurement(
+absl::optional<CXFA_Measurement> CFXJSE_MapModule::GetMeasurement(
     uint32_t key) const {
   auto it = m_MeasurementMap.find(key);
   if (it == m_MeasurementMap.end())
diff --git a/fxjs/xfa/cfxjse_mapmodule.h b/fxjs/xfa/cfxjse_mapmodule.h
index ce8fa07..ff641c5 100644
--- a/fxjs/xfa/cfxjse_mapmodule.h
+++ b/fxjs/xfa/cfxjse_mapmodule.h
@@ -27,9 +27,9 @@
   void SetValue(uint32_t key, int32_t value);
   void SetString(uint32_t key, const WideString& wsString);
   void SetMeasurement(uint32_t key, const CXFA_Measurement& measurement);
-  Optional<int32_t> GetValue(uint32_t key) const;
-  Optional<WideString> GetString(uint32_t key) const;
-  Optional<CXFA_Measurement> GetMeasurement(uint32_t key) const;
+  absl::optional<int32_t> GetValue(uint32_t key) const;
+  absl::optional<WideString> GetString(uint32_t key) const;
+  absl::optional<CXFA_Measurement> GetMeasurement(uint32_t key) const;
   bool HasKey(uint32_t key) const;
   void RemoveKey(uint32_t key);
   void MergeDataFrom(const CFXJSE_MapModule* pSrc);
diff --git a/fxjs/xfa/cfxjse_resolveprocessor.cpp b/fxjs/xfa/cfxjse_resolveprocessor.cpp
index 3bcf9f3..243cb9e 100644
--- a/fxjs/xfa/cfxjse_resolveprocessor.cpp
+++ b/fxjs/xfa/cfxjse_resolveprocessor.cpp
@@ -241,7 +241,7 @@
     CXFA_Object* curNode,
     CFXJSE_Engine::ResolveResult* rnd,
     WideStringView strAttr) {
-  Optional<XFA_SCRIPTATTRIBUTEINFO> info =
+  absl::optional<XFA_SCRIPTATTRIBUTEINFO> info =
       XFA_GetScriptAttributeByName(curNode->GetElementType(), strAttr);
   if (!info.has_value())
     return false;
diff --git a/fxjs/xfa/cjx_field.cpp b/fxjs/xfa/cjx_field.cpp
index 4ebf524..20634e1 100644
--- a/fxjs/xfa/cjx_field.cpp
+++ b/fxjs/xfa/cjx_field.cpp
@@ -111,7 +111,7 @@
   if (!node->IsWidgetReady())
     return CJS_Result::Success(runtime->NewNull());
 
-  Optional<WideString> value = node->GetChoiceListItem(iIndex, true);
+  absl::optional<WideString> value = node->GetChoiceListItem(iIndex, true);
   if (!value.has_value())
     return CJS_Result::Success(runtime->NewNull());
 
@@ -177,7 +177,7 @@
   if (!node->IsWidgetReady())
     return CJS_Result::Success(runtime->NewNull());
 
-  Optional<WideString> value = node->GetChoiceListItem(iIndex, false);
+  absl::optional<WideString> value = node->GetChoiceListItem(iIndex, false);
   if (!value.has_value())
     return CJS_Result::Success(runtime->NewNull());
 
diff --git a/fxjs/xfa/cjx_form.cpp b/fxjs/xfa/cjx_form.cpp
index ace4931..972b6dc 100644
--- a/fxjs/xfa/cjx_form.cpp
+++ b/fxjs/xfa/cjx_form.cpp
@@ -142,7 +142,8 @@
     return;
   }
 
-  Optional<WideString> checksum = TryAttribute(XFA_Attribute::Checksum, false);
+  absl::optional<WideString> checksum =
+      TryAttribute(XFA_Attribute::Checksum, false);
   *pValue = fxv8::NewStringHelper(
       pIsolate,
       checksum.has_value() ? checksum.value().ToUTF8().AsStringView() : "");
diff --git a/fxjs/xfa/cjx_hostpseudomodel.cpp b/fxjs/xfa/cjx_hostpseudomodel.cpp
index 8fec287..3a24157 100644
--- a/fxjs/xfa/cjx_hostpseudomodel.cpp
+++ b/fxjs/xfa/cjx_hostpseudomodel.cpp
@@ -295,7 +295,7 @@
     constexpr Mask<XFA_ResolveFlag> kFlags = {XFA_ResolveFlag::kChildren,
                                               XFA_ResolveFlag::kParent,
                                               XFA_ResolveFlag::kSiblings};
-    Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+    absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
         pScriptContext->ResolveObjects(
             pObject, runtime->ToWideString(params[0]).AsStringView(), kFlags);
     if (!maybeResult.has_value() ||
@@ -381,7 +381,7 @@
     constexpr Mask<XFA_ResolveFlag> kFlags = {XFA_ResolveFlag::kChildren,
                                               XFA_ResolveFlag::kParent,
                                               XFA_ResolveFlag::kSiblings};
-    Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+    absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
         pScriptContext->ResolveObjects(pObject, wsName.AsStringView(), kFlags);
     if (!maybeResult.has_value() ||
         !maybeResult.value().objects.front()->IsNode())
@@ -444,7 +444,7 @@
       constexpr Mask<XFA_ResolveFlag> kFlags = {XFA_ResolveFlag::kChildren,
                                                 XFA_ResolveFlag::kParent,
                                                 XFA_ResolveFlag::kSiblings};
-      Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+      absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
           pScriptContext->ResolveObjects(
               pObject, runtime->ToWideString(params[0]).AsStringView(), kFlags);
       if (!maybeResult.has_value() ||
diff --git a/fxjs/xfa/cjx_node.cpp b/fxjs/xfa/cjx_node.cpp
index f6ac5e7..e7a263d 100644
--- a/fxjs/xfa/cjx_node.cpp
+++ b/fxjs/xfa/cjx_node.cpp
@@ -181,7 +181,7 @@
     return CJS_Result::Failure(JSMessage::kParamError);
 
   WideString expression = runtime->ToWideString(params[0]);
-  Optional<XFA_ATTRIBUTEINFO> attr =
+  absl::optional<XFA_ATTRIBUTEINFO> attr =
       XFA_GetAttributeByName(expression.AsStringView());
   if (attr.has_value() && HasAttribute(attr.value().attribute))
     return CJS_Result::Success(runtime->NewBoolean(true));
diff --git a/fxjs/xfa/cjx_object.cpp b/fxjs/xfa/cjx_object.cpp
index 0c8e5fe..ef3051f 100644
--- a/fxjs/xfa/cjx_object.cpp
+++ b/fxjs/xfa/cjx_object.cpp
@@ -209,7 +209,7 @@
                                     bool bNotify) {
   switch (GetXFANode()->GetAttributeType(eAttr)) {
     case XFA_AttributeType::Enum: {
-      Optional<XFA_AttributeValue> item =
+      absl::optional<XFA_AttributeValue> item =
           XFA_GetAttributeValueByName(wsValue.AsStringView());
       SetEnum(eAttr,
               item.has_value() ? item.value()
@@ -239,7 +239,7 @@
 
 void CJX_Object::SetAttributeByString(WideStringView wsAttr,
                                       const WideString& wsValue) {
-  Optional<XFA_ATTRIBUTEINFO> attr = XFA_GetAttributeByName(wsAttr);
+  absl::optional<XFA_ATTRIBUTEINFO> attr = XFA_GetAttributeByName(wsAttr);
   if (attr.has_value()) {
     SetAttributeByEnum(attr.value().attribute, wsValue, true);
     return;
@@ -249,8 +249,8 @@
 }
 
 WideString CJX_Object::GetAttributeByString(WideStringView attr) const {
-  Optional<WideString> result;
-  Optional<XFA_ATTRIBUTEINFO> enum_attr = XFA_GetAttributeByName(attr);
+  absl::optional<WideString> result;
+  absl::optional<XFA_ATTRIBUTEINFO> enum_attr = XFA_GetAttributeByName(attr);
   if (enum_attr.has_value())
     result = TryAttribute(enum_attr.value().attribute, true);
   else
@@ -262,11 +262,11 @@
   return TryAttribute(attr, true).value_or(WideString());
 }
 
-Optional<WideString> CJX_Object::TryAttribute(XFA_Attribute eAttr,
-                                              bool bUseDefault) const {
+absl::optional<WideString> CJX_Object::TryAttribute(XFA_Attribute eAttr,
+                                                    bool bUseDefault) const {
   switch (GetXFANode()->GetAttributeType(eAttr)) {
     case XFA_AttributeType::Enum: {
-      Optional<XFA_AttributeValue> value = TryEnum(eAttr, bUseDefault);
+      absl::optional<XFA_AttributeValue> value = TryEnum(eAttr, bUseDefault);
       if (!value.has_value())
         return absl::nullopt;
       return WideString::FromASCII(XFA_AttributeValueToName(value.value()));
@@ -275,19 +275,19 @@
       return TryCData(eAttr, bUseDefault);
 
     case XFA_AttributeType::Boolean: {
-      Optional<bool> value = TryBoolean(eAttr, bUseDefault);
+      absl::optional<bool> value = TryBoolean(eAttr, bUseDefault);
       if (!value.has_value())
         return absl::nullopt;
       return WideString(value.value() ? L"1" : L"0");
     }
     case XFA_AttributeType::Integer: {
-      Optional<int32_t> iValue = TryInteger(eAttr, bUseDefault);
+      absl::optional<int32_t> iValue = TryInteger(eAttr, bUseDefault);
       if (!iValue.has_value())
         return absl::nullopt;
       return WideString::Format(L"%d", iValue.value());
     }
     case XFA_AttributeType::Measure: {
-      Optional<CXFA_Measurement> value = TryMeasure(eAttr, bUseDefault);
+      absl::optional<CXFA_Measurement> value = TryMeasure(eAttr, bUseDefault);
       if (!value.has_value())
         return absl::nullopt;
       return value->ToString();
@@ -302,10 +302,10 @@
   RemoveMapModuleKey(GetMapKey_Custom(wsAttr));
 }
 
-Optional<bool> CJX_Object::TryBoolean(XFA_Attribute eAttr,
-                                      bool bUseDefault) const {
+absl::optional<bool> CJX_Object::TryBoolean(XFA_Attribute eAttr,
+                                            bool bUseDefault) const {
   uint32_t key = GetMapKey_Element(GetXFAObject()->GetElementType(), eAttr);
-  Optional<int32_t> value = GetMapModuleValueFollowingChain(key);
+  absl::optional<int32_t> value = GetMapModuleValueFollowingChain(key);
   if (value.has_value())
     return !!value.value();
   if (!bUseDefault)
@@ -337,10 +337,10 @@
   return TryInteger(eAttr, true).value_or(0);
 }
 
-Optional<int32_t> CJX_Object::TryInteger(XFA_Attribute eAttr,
-                                         bool bUseDefault) const {
+absl::optional<int32_t> CJX_Object::TryInteger(XFA_Attribute eAttr,
+                                               bool bUseDefault) const {
   uint32_t key = GetMapKey_Element(GetXFAObject()->GetElementType(), eAttr);
-  Optional<int32_t> value = GetMapModuleValueFollowingChain(key);
+  absl::optional<int32_t> value = GetMapModuleValueFollowingChain(key);
   if (value.has_value())
     return value.value();
   if (!bUseDefault)
@@ -348,10 +348,10 @@
   return GetXFANode()->GetDefaultInteger(eAttr);
 }
 
-Optional<XFA_AttributeValue> CJX_Object::TryEnum(XFA_Attribute eAttr,
-                                                 bool bUseDefault) const {
+absl::optional<XFA_AttributeValue> CJX_Object::TryEnum(XFA_Attribute eAttr,
+                                                       bool bUseDefault) const {
   uint32_t key = GetMapKey_Element(GetXFAObject()->GetElementType(), eAttr);
-  Optional<int32_t> value = GetMapModuleValueFollowingChain(key);
+  absl::optional<int32_t> value = GetMapModuleValueFollowingChain(key);
   if (value.has_value())
     return static_cast<XFA_AttributeValue>(value.value());
   if (!bUseDefault)
@@ -386,10 +386,11 @@
     OnChanged(eAttr, false);
 }
 
-Optional<CXFA_Measurement> CJX_Object::TryMeasure(XFA_Attribute eAttr,
-                                                  bool bUseDefault) const {
+absl::optional<CXFA_Measurement> CJX_Object::TryMeasure(
+    XFA_Attribute eAttr,
+    bool bUseDefault) const {
   uint32_t key = GetMapKey_Element(GetXFAObject()->GetElementType(), eAttr);
-  Optional<CXFA_Measurement> result =
+  absl::optional<CXFA_Measurement> result =
       GetMapModuleMeasurementFollowingChain(key);
   if (result.has_value())
     return result.value();
@@ -398,8 +399,8 @@
   return GetXFANode()->GetDefaultMeasurement(eAttr);
 }
 
-Optional<float> CJX_Object::TryMeasureAsFloat(XFA_Attribute attr) const {
-  Optional<CXFA_Measurement> measure = TryMeasure(attr, false);
+absl::optional<float> CJX_Object::TryMeasureAsFloat(XFA_Attribute attr) const {
+  absl::optional<CXFA_Measurement> measure = TryMeasure(attr, false);
   if (!measure.has_value())
     return absl::nullopt;
   return measure->ToUnit(XFA_Unit::Pt);
@@ -427,7 +428,7 @@
                               bool bScriptModify) {
   CXFA_Node* xfaObj = GetXFANode();
   uint32_t key = GetMapKey_Element(xfaObj->GetElementType(), eAttr);
-  Optional<WideString> old_value = GetMapModuleString(key);
+  absl::optional<WideString> old_value = GetMapModuleString(key);
   if (!old_value.has_value() || old_value.value() != wsValue) {
     if (bNotify)
       OnChanging(eAttr);
@@ -475,7 +476,7 @@
   auto* xfaObj = GetXFANode();
   uint32_t key =
       GetMapKey_Element(xfaObj->GetElementType(), XFA_Attribute::Value);
-  Optional<WideString> old_value = GetMapModuleString(key);
+  absl::optional<WideString> old_value = GetMapModuleString(key);
   if (!old_value.has_value() || old_value.value() != wsValue) {
     if (bNotify)
       OnChanging(XFA_Attribute::Value);
@@ -487,10 +488,10 @@
   }
 }
 
-Optional<WideString> CJX_Object::TryCData(XFA_Attribute eAttr,
-                                          bool bUseDefault) const {
+absl::optional<WideString> CJX_Object::TryCData(XFA_Attribute eAttr,
+                                                bool bUseDefault) const {
   uint32_t key = GetMapKey_Element(GetXFAObject()->GetElementType(), eAttr);
-  Optional<WideString> value = GetMapModuleStringFollowingChain(key);
+  absl::optional<WideString> value = GetMapModuleStringFollowingChain(key);
   if (value.has_value())
     return value;
 
@@ -504,7 +505,7 @@
                                      int32_t value,
                                      bool bNotify) {
   uint32_t key = GetMapKey_Element(GetXFAObject()->GetElementType(), eAttr);
-  Optional<int32_t> old_value = GetMapModuleValue(key);
+  absl::optional<int32_t> old_value = GetMapModuleValue(key);
   if (!old_value.has_value() || old_value.value() != value) {
     if (bNotify)
       OnChanging(eAttr);
@@ -614,7 +615,7 @@
     case XFA_ObjectType::ContentNode: {
       WideString wsContentType;
       if (GetXFANode()->GetElementType() == XFA_Element::ExData) {
-        Optional<WideString> ret =
+        absl::optional<WideString> ret =
             TryAttribute(XFA_Attribute::ContentType, false);
         if (ret.has_value())
           wsContentType = ret.value();
@@ -681,8 +682,8 @@
   return TryContent(bScriptModify, true).value_or(WideString());
 }
 
-Optional<WideString> CJX_Object::TryContent(bool bScriptModify,
-                                            bool bProto) const {
+absl::optional<WideString> CJX_Object::TryContent(bool bScriptModify,
+                                                  bool bProto) const {
   CXFA_Node* pNode = nullptr;
   switch (GetXFANode()->GetObjectType()) {
     case XFA_ObjectType::ContainerNode:
@@ -709,7 +710,7 @@
       if (!pContentRawDataNode) {
         XFA_Element element = XFA_Element::Sharptext;
         if (GetXFANode()->GetElementType() == XFA_Element::ExData) {
-          Optional<WideString> contentType =
+          absl::optional<WideString> contentType =
               TryAttribute(XFA_Attribute::ContentType, false);
           if (contentType.has_value()) {
             if (contentType.value().EqualsASCII("text/html"))
@@ -743,7 +744,7 @@
   return absl::nullopt;
 }
 
-Optional<WideString> CJX_Object::TryNamespace() const {
+absl::optional<WideString> CJX_Object::TryNamespace() const {
   if (GetXFANode()->IsModelNode() ||
       GetXFANode()->GetElementType() == XFA_Element::Packet) {
     CFX_XMLNode* pXMLNode = GetXFANode()->GetXMLMappingNode();
@@ -808,21 +809,21 @@
   CreateMapModule()->SetMeasurement(key, value);
 }
 
-Optional<int32_t> CJX_Object::GetMapModuleValue(uint32_t key) const {
+absl::optional<int32_t> CJX_Object::GetMapModuleValue(uint32_t key) const {
   CFXJSE_MapModule* pModule = GetMapModule();
   if (!pModule)
     return absl::nullopt;
   return pModule->GetValue(key);
 }
 
-Optional<WideString> CJX_Object::GetMapModuleString(uint32_t key) const {
+absl::optional<WideString> CJX_Object::GetMapModuleString(uint32_t key) const {
   CFXJSE_MapModule* pModule = GetMapModule();
   if (!pModule)
     return absl::nullopt;
   return pModule->GetString(key);
 }
 
-Optional<CXFA_Measurement> CJX_Object::GetMapModuleMeasurement(
+absl::optional<CXFA_Measurement> CJX_Object::GetMapModuleMeasurement(
     uint32_t key) const {
   CFXJSE_MapModule* pModule = GetMapModule();
   if (!pModule)
@@ -830,7 +831,7 @@
   return pModule->GetMeasurement(key);
 }
 
-Optional<int32_t> CJX_Object::GetMapModuleValueFollowingChain(
+absl::optional<int32_t> CJX_Object::GetMapModuleValueFollowingChain(
     uint32_t key) const {
   std::set<const CXFA_Node*> visited;
   for (const CXFA_Node* pNode = GetXFANode(); pNode;
@@ -838,7 +839,7 @@
     if (!visited.insert(pNode).second)
       break;
 
-    Optional<int32_t> result = pNode->JSObject()->GetMapModuleValue(key);
+    absl::optional<int32_t> result = pNode->JSObject()->GetMapModuleValue(key);
     if (result.has_value())
       return result;
 
@@ -848,7 +849,7 @@
   return absl::nullopt;
 }
 
-Optional<WideString> CJX_Object::GetMapModuleStringFollowingChain(
+absl::optional<WideString> CJX_Object::GetMapModuleStringFollowingChain(
     uint32_t key) const {
   std::set<const CXFA_Node*> visited;
   for (const CXFA_Node* pNode = GetXFANode(); pNode;
@@ -856,7 +857,8 @@
     if (!visited.insert(pNode).second)
       break;
 
-    Optional<WideString> result = pNode->JSObject()->GetMapModuleString(key);
+    absl::optional<WideString> result =
+        pNode->JSObject()->GetMapModuleString(key);
     if (result.has_value())
       return result;
 
@@ -866,15 +868,15 @@
   return absl::nullopt;
 }
 
-Optional<CXFA_Measurement> CJX_Object::GetMapModuleMeasurementFollowingChain(
-    uint32_t key) const {
+absl::optional<CXFA_Measurement>
+CJX_Object::GetMapModuleMeasurementFollowingChain(uint32_t key) const {
   std::set<const CXFA_Node*> visited;
   for (const CXFA_Node* pNode = GetXFANode(); pNode;
        pNode = pNode->GetTemplateNodeIfExists()) {
     if (!visited.insert(pNode).second)
       break;
 
-    Optional<CXFA_Measurement> result =
+    absl::optional<CXFA_Measurement> result =
         pNode->JSObject()->GetMapModuleMeasurement(key);
     if (result.has_value())
       return result;
@@ -1006,7 +1008,7 @@
 
   CXFA_Node* pProtoNode = nullptr;
   if (!wsSOM.IsEmpty()) {
-    Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+    absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
         GetDocument()->GetScriptContext()->ResolveObjects(
             pProtoRoot, wsSOM.AsStringView(),
             Mask<XFA_ResolveFlag>{
diff --git a/fxjs/xfa/cjx_object.h b/fxjs/xfa/cjx_object.h
index 4034f1d..a68ed0e 100644
--- a/fxjs/xfa/cjx_object.h
+++ b/fxjs/xfa/cjx_object.h
@@ -125,8 +125,8 @@
   bool HasAttribute(XFA_Attribute eAttr) const;
   WideString GetAttributeByString(WideStringView attr) const;
   WideString GetAttributeByEnum(XFA_Attribute attr) const;
-  Optional<WideString> TryAttribute(XFA_Attribute eAttr,
-                                    bool bUseDefault) const;
+  absl::optional<WideString> TryAttribute(XFA_Attribute eAttr,
+                                          bool bUseDefault) const;
   void SetAttributeByEnum(XFA_Attribute eAttr,
                           const WideString& wsValue,
                           bool bNotify);
@@ -134,7 +134,7 @@
   void RemoveAttribute(WideStringView wsAttr);
 
   WideString GetContent(bool bScriptModify) const;
-  Optional<WideString> TryContent(bool bScriptModify, bool bProto) const;
+  absl::optional<WideString> TryContent(bool bScriptModify, bool bProto) const;
   void SetContent(const WideString& wsContent,
                   const WideString& wsXMLValue,
                   bool bNotify,
@@ -174,30 +174,32 @@
   JSE_PROP(ScriptSomInstanceIndex);
   JSE_PROP(ScriptSubmitFormatMode);
 
-  Optional<WideString> TryNamespace() const;
+  absl::optional<WideString> TryNamespace() const;
 
   int32_t GetInteger(XFA_Attribute eAttr) const;
-  Optional<int32_t> TryInteger(XFA_Attribute eAttr, bool bUseDefault) const;
+  absl::optional<int32_t> TryInteger(XFA_Attribute eAttr,
+                                     bool bUseDefault) const;
   void SetInteger(XFA_Attribute eAttr, int32_t iValue, bool bNotify);
 
   WideString GetCData(XFA_Attribute eAttr) const;
-  Optional<WideString> TryCData(XFA_Attribute eAttr, bool bUseDefault) const;
+  absl::optional<WideString> TryCData(XFA_Attribute eAttr,
+                                      bool bUseDefault) const;
   void SetCData(XFA_Attribute eAttr, const WideString& wsValue);
 
   XFA_AttributeValue GetEnum(XFA_Attribute eAttr) const;
-  Optional<XFA_AttributeValue> TryEnum(XFA_Attribute eAttr,
-                                       bool bUseDefault) const;
+  absl::optional<XFA_AttributeValue> TryEnum(XFA_Attribute eAttr,
+                                             bool bUseDefault) const;
   void SetEnum(XFA_Attribute eAttr, XFA_AttributeValue eValue, bool bNotify);
 
   bool GetBoolean(XFA_Attribute eAttr) const;
-  Optional<bool> TryBoolean(XFA_Attribute eAttr, bool bUseDefault) const;
+  absl::optional<bool> TryBoolean(XFA_Attribute eAttr, bool bUseDefault) const;
   void SetBoolean(XFA_Attribute eAttr, bool bValue, bool bNotify);
 
   CXFA_Measurement GetMeasure(XFA_Attribute eAttr) const;
   float GetMeasureInUnit(XFA_Attribute eAttr, XFA_Unit unit) const;
-  Optional<CXFA_Measurement> TryMeasure(XFA_Attribute eAttr,
-                                        bool bUseDefault) const;
-  Optional<float> TryMeasureAsFloat(XFA_Attribute attr) const;
+  absl::optional<CXFA_Measurement> TryMeasure(XFA_Attribute eAttr,
+                                              bool bUseDefault) const;
+  absl::optional<float> TryMeasureAsFloat(XFA_Attribute attr) const;
   void SetMeasure(XFA_Attribute eAttr,
                   const CXFA_Measurement& mValue,
                   bool bNotify);
@@ -260,12 +262,13 @@
   void SetMapModuleValue(uint32_t key, int32_t value);
   void SetMapModuleString(uint32_t key, const WideString& wsValue);
   void SetMapModuleMeasurement(uint32_t key, const CXFA_Measurement& value);
-  Optional<int32_t> GetMapModuleValue(uint32_t key) const;
-  Optional<WideString> GetMapModuleString(uint32_t key) const;
-  Optional<CXFA_Measurement> GetMapModuleMeasurement(uint32_t key) const;
-  Optional<int32_t> GetMapModuleValueFollowingChain(uint32_t key) const;
-  Optional<WideString> GetMapModuleStringFollowingChain(uint32_t key) const;
-  Optional<CXFA_Measurement> GetMapModuleMeasurementFollowingChain(
+  absl::optional<int32_t> GetMapModuleValue(uint32_t key) const;
+  absl::optional<WideString> GetMapModuleString(uint32_t key) const;
+  absl::optional<CXFA_Measurement> GetMapModuleMeasurement(uint32_t key) const;
+  absl::optional<int32_t> GetMapModuleValueFollowingChain(uint32_t key) const;
+  absl::optional<WideString> GetMapModuleStringFollowingChain(
+      uint32_t key) const;
+  absl::optional<CXFA_Measurement> GetMapModuleMeasurementFollowingChain(
       uint32_t key) const;
   bool HasMapModuleKey(uint32_t key) const;
   void RemoveMapModuleKey(uint32_t key);
diff --git a/fxjs/xfa/cjx_tree.cpp b/fxjs/xfa/cjx_tree.cpp
index 006a096..8e402b2 100644
--- a/fxjs/xfa/cjx_tree.cpp
+++ b/fxjs/xfa/cjx_tree.cpp
@@ -48,7 +48,7 @@
   if (pRefNode->GetElementType() == XFA_Element::Xfa)
     pRefNode = pScriptContext->GetThisObject();
 
-  Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+  absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
       pScriptContext->ResolveObjects(
           ToNode(pRefNode), wsExpression.AsStringView(),
           Mask<XFA_ResolveFlag>{
@@ -220,7 +220,7 @@
   pDoc->GetNodeOwner()->PersistList(pNodeList);
 
   CFXJSE_Engine* pScriptContext = pDoc->GetScriptContext();
-  Optional<CFXJSE_Engine::ResolveResult> maybeResult =
+  absl::optional<CFXJSE_Engine::ResolveResult> maybeResult =
       pScriptContext->ResolveObjects(refNode, wsExpression.AsStringView(),
                                      dwFlag);