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

Source/modules/plugins/DOMMimeTypeArray.cpp

 /*
  *  Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *  Copyright (C) 2008 Apple Inc. All rights reserved.
  *
  *  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,
@@ skipping 28 matching lines @@
 }
 
 unsigned DOMMimeTypeArray::length() const
 {
     PluginData* data = getPluginData();
     if (!data)
         return 0;
     return data->mimes().size();
 }
 
-PassRefPtrWillBeRawPtr<DOMMimeType> DOMMimeTypeArray::item(unsigned index)
+DOMMimeType* DOMMimeTypeArray::item(unsigned index)
 {
     PluginData* data = getPluginData();
     if (!data)
         return nullptr;
     const Vector<MimeClassInfo>& mimes = data->mimes();
     if (index >= mimes.size())
         return nullptr;
     return DOMMimeType::create(data, m_frame, index);
 }
 
-PassRefPtrWillBeRawPtr<DOMMimeType> DOMMimeTypeArray::namedItem(const AtomicString& propertyName)
+DOMMimeType* DOMMimeTypeArray::namedItem(const AtomicString& propertyName)
 {
     PluginData* data = getPluginData();
     if (!data)
         return nullptr;
     const Vector<MimeClassInfo>& mimes = data->mimes();
     for (unsigned i = 0; i < mimes.size(); ++i) {
         if (mimes[i].type == propertyName)
             return DOMMimeType::create(data, m_frame, i);
     }
     return nullptr;
 }
 
 PluginData* DOMMimeTypeArray::getPluginData() const
 {
     if (!m_frame)
         return nullptr;
     Page* p = m_frame->page();
     if (!p)
         return nullptr;
     return p->pluginData();
 }
 
 } // namespace blink