Use mayNotBeMainThread() for wrapper optimization

third_party/WebKit/Source/core/dom/DocumentTest.cpp

Index: third_party/WebKit/Source/core/dom/DocumentTest.cpp
diff --git a/third_party/WebKit/Source/core/dom/DocumentTest.cpp b/third_party/WebKit/Source/core/dom/DocumentTest.cpp
index d9e2f2fa11a05e89f2ccce87903289a10a8db15c..193e693cd02d509b8a112c42640c0de7f71521f0 100644
--- a/third_party/WebKit/Source/core/dom/DocumentTest.cpp
+++ b/third_party/WebKit/Source/core/dom/DocumentTest.cpp
@@ -53,6 +53,7 @@ class DocumentTest : public ::testing::Test {
 
   void TearDown() override { ThreadState::current()->collectAllGarbage(); }
 
+  LocalFrame& frame() const { return m_dummyPageHolder->frame(); }
   Document& document() const { return m_dummyPageHolder->document(); }
   Page& page() const { return m_dummyPageHolder->page(); }
 
@@ -575,6 +576,9 @@ TEST_F(DocumentTest, SynchronousMutationNotifieReplaceChild) {
 }
 
 TEST_F(DocumentTest, SynchronousMutationNotifierSplitTextNode) {
+  ScriptState* scriptState = ScriptState::forMainWorld(&frame());
+  ScriptState::Scope scope(scriptState);
+
   auto& observer = *new TestSynchronousMutationObserver(document());
 
   Text* splitSample = document().createTextNode("0123456789");