Disallow script execution after unload event dispatch in frame detach.

Source/core/frame/LocalFrame.cpp

Index: Source/core/frame/LocalFrame.cpp
diff --git a/Source/core/frame/LocalFrame.cpp b/Source/core/frame/LocalFrame.cpp
index 56e289040b2b5e27f1dbe0f989bca8cc83752f11..5c473a10669f085d12946f9ed9c445dd462b1b5c 100644
--- a/Source/core/frame/LocalFrame.cpp
+++ b/Source/core/frame/LocalFrame.cpp
@@ -64,6 +64,7 @@
 #include "core/svg/SVGDocumentExtensions.h"
 #include "platform/DragImage.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "platform/ScriptForbiddenScope.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/text/TextStream.h"
@@ -195,6 +196,8 @@ void LocalFrame::detach()
     m_loader.stopAllLoaders();
     if (!client())
         return;
+
+    ScriptForbiddenScope forbidScript;
     m_loader.detach();
     setView(nullptr);
     willDetachFrameHost();