Prerendered pages are swapped in at browser::Navigate time.

chrome/renderer/prerender/prerender_dispatcher.h

Index: chrome/renderer/prerender/prerender_dispatcher.h
diff --git a/chrome/renderer/prerender/prerender_dispatcher.h b/chrome/renderer/prerender/prerender_dispatcher.h
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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_RENDERER_PRERENDER_PRERENDER_DISPATCHER_H_
+#define CHROME_RENDERER_PRERENDER_PRERENDER_DISPATCHER_H_
+#pragma once
+
+#include <map>
+
+#include "base/compiler_specific.h"
+#include "content/public/renderer/render_process_observer.h"
+
+class GURL;
+
+namespace prerender {
+
+// PrerenderDispatcher keeps track of which URLs are being prerendered. There
+// is only one PrerenderDispatcher per render process, and it will only be
+// aware of prerenders that are triggered by this render process.
+class PrerenderDispatcher : public content::RenderProcessObserver {
+ public:
+  PrerenderDispatcher();
+  virtual ~PrerenderDispatcher();
+
+  bool IsPrerenderURL(const GURL & url) const;
+
+ private:
+  void OnAddPrerenderURL(const GURL& url);
+  void OnRemovePrerenderURL(const GURL& url);
+
+  // RenderProcessObserver:
+  virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  typedef std::map<GURL, int> PrerenderMap;
+  PrerenderMap prerender_urls_;
+};
+
+}  // namespace prerender
+
+#endif  // CHROME_RENDERER_PRERENDER_PRERENDER_DISPATCHER_H_