fpdfsdk/ differences with XFA (for didactic purposes only).

fpdfsdk/src/javascript/JS_Context.cpp

Index: fpdfsdk/src/javascript/JS_Context.cpp
diff --git a/fpdfsdk/src/javascript/JS_Context.cpp b/fpdfsdk/src/javascript/JS_Context.cpp
index 8d54cddc4197f26fd4e19fea9a1ebbb0675f01fc..e59b1a77ed04b88ea6fd1d365aa3d45c9016d92d 100644
--- a/fpdfsdk/src/javascript/JS_Context.cpp
+++ b/fpdfsdk/src/javascript/JS_Context.cpp
@@ -35,6 +35,9 @@ CPDFDoc_Environment* CJS_Context::GetReaderApp() {
 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
   v8::HandleScope handle_scope(m_pRuntime->GetIsolate());
   v8::Local<v8::Context> context = m_pRuntime->NewJSContext();
   v8::Context::Scope context_scope(context);