[WIP]Issue FrameDestructionObserver::frameDestroyed() notification on detach.

Source/core/frame/LocalDOMWindow.cpp

Index: Source/core/frame/LocalDOMWindow.cpp
diff --git a/Source/core/frame/LocalDOMWindow.cpp b/Source/core/frame/LocalDOMWindow.cpp
index 3908ad26b798a821da5d3ca7cab9a641f5efd118..78d3b125bb764cb912b44dd1b76e41d895d8009b 100644
--- a/Source/core/frame/LocalDOMWindow.cpp
+++ b/Source/core/frame/LocalDOMWindow.cpp
@@ -144,6 +144,12 @@ void LocalDOMWindow::WindowFrameObserver::willDetachFrameHost()
     m_window->willDetachFrameHost();
 }
 
+void LocalDOMWindow::WindowFrameObserver::frameDestroyed()
+{
+    m_window->frameDestroyed();
+    FrameDestructionObserver::frameDestroyed();
+}
+
 class PostMessageTimer final : public NoBaseWillBeGarbageCollectedFinalized<PostMessageTimer>, public SuspendableTimer {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(PostMessageTimer);
 public:
@@ -595,6 +601,12 @@ void LocalDOMWindow::willDetachFrameHost()
     LocalDOMWindow::notifyContextDestroyed();
 }
 
+void LocalDOMWindow::frameDestroyed()
+{
+    willDestroyDocumentInFrame();
+    m_properties.clear();
+}
+
 void LocalDOMWindow::willDestroyDocumentInFrame()
 {
     for (const auto& domWindowProperty : m_properties)
@@ -619,8 +631,7 @@ void LocalDOMWindow::unregisterProperty(DOMWindowProperty* property)
 
 void LocalDOMWindow::reset()
 {
-    willDestroyDocumentInFrame();
-    m_properties.clear();
+    frameDestroyed();
 
     m_screen = nullptr;
     m_history = nullptr;