Oilpan: fix webkit unit tests after r194688.

Source/web/WebPluginContainerImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2014 Opera Software ASA. 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.
@@ skipping 500 matching lines @@
 }
 
 void WebPluginContainerImpl::zoomLevelChanged(double zoomLevel)
 {
     WebViewImpl* view = WebViewImpl::fromPage(m_element->document().frame()->page());
     view->fullFramePluginZoomLevelChanged(zoomLevel);
 }
 
 bool WebPluginContainerImpl::isRectTopmost(const WebRect& rect)
 {
-    if (m_element->document().isDetached())
+    if (!m_element || m_element->document().isDetached())
         return false;
 
     LocalFrame* frame = m_element->document().frame();
     if (!frame)
         return false;
 
     // hitTestResultAtPoint() takes a padding rectangle.
     // FIXME: We'll be off by 1 when the width or height is even.
     IntRect documentRect(x() + rect.x, y() + rect.y, rect.width, rect.height);
     LayoutPoint center = documentRect.center();
@@ skipping 482 matching lines @@
     for (size_t i = 0; i < cutOutRects.size(); i++)
         cutOutRects[i].move(-frameRect().x(), -frameRect().y());
 }
 
 bool WebPluginContainerImpl::pluginShouldPersist() const
 {
     return m_webPlugin->shouldPersist();
 }
 
 } // namespace blink