Make DOMWindowProperty a thin wrapper of ContextLifecycleObserver

third_party/WebKit/Source/core/frame/LocalDOMWindow.h

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.h
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.h b/third_party/WebKit/Source/core/frame/LocalDOMWindow.h
index 2d0a9d2e9eb265e04cf6db6f6dc4c3a2bc036a74..23c807e926c791abaf4e6716b26780dccc49af80 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.h
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.h
@@ -41,7 +41,6 @@ namespace blink {
 
 class CustomElementRegistry;
 class DOMWindowEventQueue;
-class DOMWindowProperty;
 class DocumentInit;
 class EventQueue;
 class FrameConsole;
@@ -169,12 +168,9 @@ class CORE_EXPORT LocalDOMWindow final : public DOMWindow,
   CustomElementRegistry* customElements() const;
   CustomElementRegistry* maybeCustomElements() const;
 
-  void registerProperty(DOMWindowProperty*);
-  void unregisterProperty(DOMWindowProperty*);
-
   void registerEventListenerObserver(EventListenerObserver*);
 
-  void frameDestroyed();
+  void contextDestroyed();
   void reset();
 
   unsigned pendingUnloadEventListeners() const;
@@ -265,8 +261,6 @@ class CORE_EXPORT LocalDOMWindow final : public DOMWindow,
 
   bool m_shouldPrintWhenFinishedLoading;
 
-  HeapHashSet<WeakMember<DOMWindowProperty>> m_properties;
-
   mutable Member<Screen> m_screen;
   mutable Member<History> m_history;
   mutable Member<BarProp> m_locationbar;