Revert of Remove DOMWindowProperty::willDetachGlobalObjectFromFrame

third_party/WebKit/Source/core/frame/DOMWindowProperty.cpp

Index: third_party/WebKit/Source/core/frame/DOMWindowProperty.cpp
diff --git a/third_party/WebKit/Source/core/frame/DOMWindowProperty.cpp b/third_party/WebKit/Source/core/frame/DOMWindowProperty.cpp
index 91337808fcf307eef5d9b96aefc438364840c6b9..6fc921dde4b0173080f791206a402c60a694b5b8 100644
--- a/third_party/WebKit/Source/core/frame/DOMWindowProperty.cpp
+++ b/third_party/WebKit/Source/core/frame/DOMWindowProperty.cpp
@@ -52,6 +52,13 @@
     m_frame = nullptr;
 }
 
+void DOMWindowProperty::willDetachGlobalObjectFromFrame()
+{
+    // If the property is getting this callback it must have been
+    // created with a LocalFrame and it should still have it.
+    ASSERT(m_frame);
+}
+
 DEFINE_TRACE(DOMWindowProperty)
 {
     visitor->trace(m_frame);