Oilpan: update plugin handling to work over plugins persisted over reattach

Source/core/html/HTMLPlugInElement.cpp

 /**
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Stefan Schimanski (1Stein@gmx.de)
  * Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 98 matching lines @@
 
 void HTMLPlugInElement::setPersistedPluginWidget(Widget* widget)
 {
     if (m_persistedPluginWidget == widget)
         return;
 #if ENABLE(OILPAN)
     if (m_persistedPluginWidget && m_persistedPluginWidget->isPluginView()) {
         LocalFrame* frame = toPluginView(m_persistedPluginWidget.get())->pluginFrame();
         ASSERT(frame);
         frame->unregisterPluginElement(this);
+        if (!widget)
+            m_persistedPluginWidget->dispose();

[haraken, 2015/09/01 14:32:25]

I'm wondering why we don't call m_persistedPluginWidget->dispose() in non-oilpan
as well.

[sof, 2015/09/01 21:37:31]

The prompt disposal (via deref() on clearing) will implicitly call dispose(),
non-Oilpan. That's where/how we left it when moving Widget / plugin containers
over to the Oilpan heap.

     }
     if (widget && widget->isPluginView()) {
         LocalFrame* frame = toPluginView(widget)->pluginFrame();
         ASSERT(frame);
         frame->registerPluginElement(this);
     }
 #endif
     m_persistedPluginWidget = widget;
 }
 
@@ skipping 504 matching lines @@
     return openShadowRoot();
 }
 
 void HTMLPlugInElement::lazyReattachIfNeeded()
 {
     if (!useFallbackContent() && needsWidgetUpdate() && layoutObject() && !isImageType())
         lazyReattachIfAttached();
 }
 
 }