Move the Widget hierarchy to the Oilpan heap.

Source/web/WebHelperPluginImpl.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 39 matching lines @@
     return plugin.leakPtr();
 }
 
 WebHelperPluginImpl::WebHelperPluginImpl()
     : m_destructionTimer(this, &WebHelperPluginImpl::reallyDestroy)
 {
 }
 
 WebHelperPluginImpl::~WebHelperPluginImpl()
 {
+#if ENABLE(OILPAN)
+    // FIXME: Oilpan: it is potentially problematic to support plugin
+    // disposal during an Oilpan GC. If it happens, we need to know
+    // and evaluate possible ways to handle it.
+    ASSERT(!ThreadState::current()->isSweepInProgress());
+    if (m_pluginContainer)
+        m_pluginContainer->dispose();
+#endif
 }
 
 bool WebHelperPluginImpl::initialize(const String& pluginType, WebLocalFrameImpl* frame)
 {
     ASSERT(!m_objectElement && !m_pluginContainer);
     if (!frame->frame()->loader().client())
         return false;
 
     m_objectElement = HTMLObjectElement::create(*frame->frame()->document(), 0, false);
     Vector<String> attributeNames;
     Vector<String> attributeValues;
     ASSERT(frame->frame()->document()->url().isValid());
-    m_pluginContainer = adoptRef(toWebPluginContainerImpl(frame->frame()->loader().client()->createPlugin(
+    m_pluginContainer = adoptRefWillBeNoop(toWebPluginContainerImpl(frame->frame()->loader().client()->createPlugin(
         m_objectElement.get(),
         frame->frame()->document()->url(),
         attributeNames,
         attributeValues,
         pluginType,
         false,
         FrameLoaderClient::AllowDetachedPlugin).leakRef()));
 
     if (!m_pluginContainer)
         return false;
@@ skipping 18 matching lines @@
 }
 
 WebPlugin* WebHelperPluginImpl::getPlugin()
 {
     ASSERT(m_pluginContainer);
     ASSERT(m_pluginContainer->plugin());
     return m_pluginContainer->plugin();
 }
 
 } // namespace blink