Track scroll event handlers in nested documents

Source/core/dom/EventHandlerRegistry.h

Index: Source/core/dom/EventHandlerRegistry.h
diff --git a/Source/core/dom/EventHandlerRegistry.h b/Source/core/dom/EventHandlerRegistry.h
index dde20641c428ccdc74705796c5dd65ab488f28c9..49d4eb550edd438cd94915ce4355abb201c9bdeb 100644
--- a/Source/core/dom/EventHandlerRegistry.h
+++ b/Source/core/dom/EventHandlerRegistry.h
@@ -5,6 +5,7 @@
 #ifndef EventHandlerRegistry_h
 #define EventHandlerRegistry_h
 
+#include "core/dom/ActiveDOMObject.h"
 #include "core/dom/DocumentSupplementable.h"
 #include "core/events/Event.h"
 #include "wtf/HashCountedSet.h"
@@ -16,7 +17,7 @@ typedef HashCountedSet<EventTarget*> EventTargetSet;
 // Registry for keeping track of event handlers. Handlers can either be
 // associated with an EventTarget or be "external" handlers which live outside
 // the DOM (e.g., WebViewImpl).
-class EventHandlerRegistry FINAL : public DocumentSupplement {
+class EventHandlerRegistry FINAL : public DocumentSupplement, private ActiveDOMObject {
 public:
     virtual ~EventHandlerRegistry();
 
@@ -52,6 +53,7 @@ public:
 
 private:
     explicit EventHandlerRegistry(Document&);
+    static EventHandlerRegistry* create(Document&);
 
     enum ChangeOperation {
         Add, // Add a new event handler.
@@ -59,6 +61,11 @@ private:
         RemoveAll // Remove any and all existing event handlers for a given target.
     };
 
+    Document* document() const;
+
+    // Inherited from ActiveDOMObject
+    virtual void stop() OVERRIDE;
+
     // Returns true if |eventType| belongs to a class this registry tracks.
     static bool eventTypeToClass(const AtomicString& eventType, EventHandlerClass* result);
 
@@ -85,7 +92,6 @@ private:
         OwnPtr<EventTargetSet> targets;
     };
 
-    Document& m_document;
     HandlerState m_eventHandlers[EventHandlerClassCount];
 };