diff --git a/fpdfsdk/javascript/cjs_context.cpp b/fpdfsdk/javascript/cjs_context.cpp
index 66a3e07..c8630ab 100644
--- a/fpdfsdk/javascript/cjs_context.cpp
+++ b/fpdfsdk/javascript/cjs_context.cpp
@@ -30,9 +30,6 @@
 FX_BOOL CJS_Context::RunScript(const CFX_WideString& script,
                                CFX_WideString* info) {
   v8::Isolate::Scope isolate_scope(m_pRuntime->GetIsolate());
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(m_pRuntime->GetIsolate());
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(m_pRuntime->GetIsolate());
   v8::Local<v8::Context> context = m_pRuntime->NewJSContext();
   v8::Context::Scope context_scope(context);
diff --git a/fpdfsdk/javascript/cjs_runtime.cpp b/fpdfsdk/javascript/cjs_runtime.cpp
index bcdc17c..9cbf1b0 100644
--- a/fpdfsdk/javascript/cjs_runtime.cpp
+++ b/fpdfsdk/javascript/cjs_runtime.cpp
@@ -88,7 +88,6 @@
 
   v8::Isolate* isolate = m_isolate;
   v8::Isolate::Scope isolate_scope(isolate);
-  v8::Locker locker(isolate);
   v8::HandleScope handle_scope(isolate);
   if (CPDFXFA_App::GetInstance()->IsJavaScriptInitialized()) {
     CJS_Context* pContext = (CJS_Context*)NewContext();
@@ -128,9 +127,6 @@
 
 void CJS_Runtime::DefineJSObjects() {
   v8::Isolate::Scope isolate_scope(GetIsolate());
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(GetIsolate());
-#endif
   v8::HandleScope handle_scope(GetIsolate());
   v8::Local<v8::Context> context = v8::Context::New(GetIsolate());
   v8::Context::Scope context_scope(context);
@@ -197,9 +193,6 @@
 void CJS_Runtime::SetReaderDocument(CPDFSDK_Document* pReaderDoc) {
   if (m_pDocument != pReaderDoc) {
     v8::Isolate::Scope isolate_scope(m_isolate);
-#ifdef PDF_ENABLE_XFA
-    v8::Locker locker(m_isolate);
-#endif
     v8::HandleScope handle_scope(m_isolate);
     v8::Local<v8::Context> context =
         v8::Local<v8::Context>::New(m_isolate, m_context);
@@ -265,7 +258,6 @@
 #ifdef PDF_ENABLE_XFA
   const FX_CHAR* name = utf8Name.c_str();
 
-  v8::Locker lock(GetIsolate());
   v8::Isolate::Scope isolate_scope(GetIsolate());
   v8::HandleScope handle_scope(GetIsolate());
   v8::Local<v8::Context> old_context = GetIsolate()->GetCurrentContext();
@@ -302,7 +294,6 @@
     return FALSE;
   const FX_CHAR* name = utf8Name.c_str();
   v8::Isolate* pIsolate = GetIsolate();
-  v8::Locker lock(pIsolate);
   v8::Isolate::Scope isolate_scope(pIsolate);
   v8::HandleScope handle_scope(pIsolate);
   v8::Local<v8::Context> context =
diff --git a/fpdfsdk/javascript/public_methods_embeddertest.cpp b/fpdfsdk/javascript/public_methods_embeddertest.cpp
index 1fc967b..80ec649 100644
--- a/fpdfsdk/javascript/public_methods_embeddertest.cpp
+++ b/fpdfsdk/javascript/public_methods_embeddertest.cpp
@@ -21,9 +21,6 @@
 
 TEST_F(PublicMethodsEmbedderTest, MakeRegularDate) {
   v8::Isolate::Scope isolate_scope(isolate());
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(isolate());
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(isolate());
   v8::Context::Scope context_scope(GetV8Context());
   bool bWrongFormat;
@@ -104,9 +101,6 @@
 
 TEST_F(PublicMethodsEmbedderTest, MakeFormatDate) {
   v8::Isolate::Scope isolate_scope(isolate());
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(isolate());
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(isolate());
   v8::Context::Scope context_scope(GetV8Context());
   CFX_WideString formatted_date;
diff --git a/fpdfsdk/jsapi/fxjs_v8.cpp b/fpdfsdk/jsapi/fxjs_v8.cpp
index a471d56..f8c2a3d 100644
--- a/fpdfsdk/jsapi/fxjs_v8.cpp
+++ b/fpdfsdk/jsapi/fxjs_v8.cpp
@@ -312,9 +312,6 @@
     ++g_isolate_ref_count;
 
   v8::Isolate::Scope isolate_scope(pIsolate);
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(pIsolate);
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(pIsolate);
   v8::Local<v8::Context> v8Context =
       v8::Context::New(pIsolate, NULL, GetGlobalObjectTemplate(pIsolate));
@@ -363,9 +360,6 @@
                          v8::Global<v8::Context>* pV8PersistentContext,
                          std::vector<v8::Global<v8::Object>*>* pStaticObjects) {
   v8::Isolate::Scope isolate_scope(pIsolate);
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(pIsolate);
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(pIsolate);
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(pIsolate, *pV8PersistentContext);
diff --git a/fpdfsdk/jsapi/fxjs_v8_embeddertest.cpp b/fpdfsdk/jsapi/fxjs_v8_embeddertest.cpp
index e89bb28..161487f 100644
--- a/fpdfsdk/jsapi/fxjs_v8_embeddertest.cpp
+++ b/fpdfsdk/jsapi/fxjs_v8_embeddertest.cpp
@@ -36,9 +36,6 @@
 
 TEST_F(FXJSV8EmbedderTest, Getters) {
   v8::Isolate::Scope isolate_scope(isolate());
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(isolate());
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(isolate());
   v8::Context::Scope context_scope(GetV8Context());
 
@@ -48,9 +45,6 @@
 
 TEST_F(FXJSV8EmbedderTest, MultipleRutimes) {
   v8::Isolate::Scope isolate_scope(isolate());
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(isolate());
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(isolate());
 
   v8::Global<v8::Context> global_context1;
diff --git a/testing/js_embedder_test.cpp b/testing/js_embedder_test.cpp
index 4815cd5..bdd1573 100644
--- a/testing/js_embedder_test.cpp
+++ b/testing/js_embedder_test.cpp
@@ -19,9 +19,6 @@
   EmbedderTest::SetUp();
 
   v8::Isolate::Scope isolate_scope(m_pIsolate);
-#ifdef PDF_ENABLE_XFA
-  v8::Locker locker(m_pIsolate);
-#endif  // PDF_ENABLE_XFA
   v8::HandleScope handle_scope(m_pIsolate);
   FXJS_PerIsolateData::SetUp(m_pIsolate);
   FXJS_InitializeRuntime(m_pIsolate, nullptr, &m_pPersistentContext,
diff --git a/xfa/fxjse/runtime.cpp b/xfa/fxjse/runtime.cpp
index 64d685b..70d90c4 100644
--- a/xfa/fxjse/runtime.cpp
+++ b/xfa/fxjse/runtime.cpp
@@ -36,12 +36,9 @@
 }
 
 static void FXJSE_Runtime_DisposeCallback(v8::Isolate* pIsolate) {
-  {
-    v8::Locker locker(pIsolate);
-    if (FXJS_PerIsolateData* pData = FXJS_PerIsolateData::Get(pIsolate)) {
-      delete pData->m_pFXJSERuntimeData;
-      pData->m_pFXJSERuntimeData = nullptr;
-    }
+  if (FXJS_PerIsolateData* pData = FXJS_PerIsolateData::Get(pIsolate)) {
+    delete pData->m_pFXJSERuntimeData;
+    pData->m_pFXJSERuntimeData = nullptr;
   }
   pIsolate->Dispose();
 }
diff --git a/xfa/fxjse/scope_inline.h b/xfa/fxjse/scope_inline.h
index 90b20fc..8ef9c85 100644
--- a/xfa/fxjse/scope_inline.h
+++ b/xfa/fxjse/scope_inline.h
@@ -14,7 +14,6 @@
  public:
   explicit CFXJSE_ScopeUtil_IsolateHandle(v8::Isolate* pIsolate)
       : m_isolate(pIsolate),
-        m_locker(pIsolate),
         m_iscope(pIsolate),
         m_hscope(pIsolate) {}
   v8::Isolate* GetIsolate() { return m_isolate; }
@@ -27,7 +26,6 @@
   void operator delete(void*, size_t) = delete;
 
   v8::Isolate* m_isolate;
-  v8::Locker m_locker;
   v8::Isolate::Scope m_iscope;
   v8::HandleScope m_hscope;
 };