Add relTypes() to WebPrerender.h.

Source/platform/exported/WebPrerender.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 69 matching lines @@
 bool WebPrerender::isNull() const
 {
     return m_private.isNull();
 }
 
 WebURL WebPrerender::url() const
 {
     return WebURL(m_private->url());
 }
 
+unsigned WebPrerender::relTypes() const
+{
+    // For now, all prerenders have RelTypePrerender.
+    // TODO: Once https://codereview.chromium.org/113803003/ lands in Chrome, re-land r164241 to set this correctly.
+    return PrerenderRelTypePrerender;
+}
+
 WebString WebPrerender::referrer() const
 {
     return m_private->referrer();
 }
 
 WebReferrerPolicy WebPrerender::referrerPolicy() const
 {
     return static_cast<WebReferrerPolicy>(m_private->referrerPolicy());
 }
 
@@ skipping 24 matching lines @@
 {
     m_private->didSendLoadForPrerender();
 }
 
 void WebPrerender::didSendDOMContentLoadedForPrerender()
 {
     m_private->didSendDOMContentLoadedForPrerender();
 }
 
 } // namespace blink