Implement HTMLMarqueeElement's animation in private scripts

Source/bindings/core/v8/PrivateScriptRunner.cpp

Index: Source/bindings/core/v8/PrivateScriptRunner.cpp
diff --git a/Source/bindings/core/v8/PrivateScriptRunner.cpp b/Source/bindings/core/v8/PrivateScriptRunner.cpp
index 491578038954b98bb5ccf68ea57d0f01cf68c269..eb80fbffea257c20aaf0faafc8ed79cd51cb586a 100644
--- a/Source/bindings/core/v8/PrivateScriptRunner.cpp
+++ b/Source/bindings/core/v8/PrivateScriptRunner.cpp
@@ -98,6 +98,11 @@ static void initializeHolderIfNeeded(ScriptState* scriptState, v8::Handle<v8::Ob
                 RELEASE_ASSERT_NOT_REACHED();
             }
         }
+
+        if (classObject->GetPrototype() != holderObject->GetPrototype())
+            classObject->SetPrototype(holderObject->GetPrototype());
+        holderObject->SetPrototype(classObject);
+
         isInitialized = v8Boolean(true, isolate);
         V8HiddenValue::setHiddenValue(isolate, holderObject, V8HiddenValue::privateScriptObjectIsInitialized(isolate), isInitialized);
     }