Oilpan: have Navigator plugin objects on the heap by default.

Source/modules/plugins/DOMPlugin.cpp

 /*
  *  Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 42 matching lines @@
 String DOMPlugin::description() const
 {
     return pluginInfo().desc;
 }
 
 unsigned DOMPlugin::length() const
 {
     return pluginInfo().mimes.size();
 }
 
-PassRefPtrWillBeRawPtr<DOMMimeType> DOMPlugin::item(unsigned index)
+DOMMimeType* DOMPlugin::item(unsigned index)
 {
     if (index >= pluginInfo().mimes.size())
         return nullptr;
 
     const MimeClassInfo& mime = pluginInfo().mimes[index];
 
     const Vector<MimeClassInfo>& mimes = m_pluginData->mimes();
     for (unsigned i = 0; i < mimes.size(); ++i) {
         if (mimes[i] == mime && m_pluginData->mimePluginIndices()[i] == m_index)
             return DOMMimeType::create(m_pluginData.get(), frame(), i);
     }
     return nullptr;
 }
 
-PassRefPtrWillBeRawPtr<DOMMimeType> DOMPlugin::namedItem(const AtomicString& propertyName)
+DOMMimeType* DOMPlugin::namedItem(const AtomicString& propertyName)
 {
     const Vector<MimeClassInfo>& mimes = m_pluginData->mimes();
     for (unsigned i = 0; i < mimes.size(); ++i) {
         if (mimes[i].type == propertyName)
             return DOMMimeType::create(m_pluginData.get(), frame(), i);
     }
     return nullptr;
 }
 
 } // namespace blink