Add Perceived PageLoad Time (PPLT) metrics for Prerender Experiments,...

chrome/browser/prerender/prerender_plt_recorder.h

Index: chrome/browser/prerender/prerender_plt_recorder.h
===================================================================
--- chrome/browser/prerender/prerender_plt_recorder.h	(revision 0)
+++ chrome/browser/prerender/prerender_plt_recorder.h	(revision 0)
@@ -0,0 +1,48 @@
+// Copyright (c) 2011 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_BROWSER_PRERENDER_PRERENDER_PLT_RECORDER_H_
+#define CHROME_BROWSER_PRERENDER_PRERENDER_PLT_RECORDER_H_
+#pragma once
+
+#include <list>
+#include <vector>
+
+#include "base/scoped_ptr.h"
+#include "base/time.h"
+#include "chrome/browser/tab_contents/web_navigation_observer.h"
+#include "googleurl/src/gurl.h"
+
+class PrerenderContents;
+class Profile;
+class TabContents;
+
+// PrerenderPLTRecorder is responsible for recording perceived pageload times
+// to compare PLT's with prerendering enabled and disabled.
+class PrerenderPLTRecorder : public WebNavigationObserver {
+ public:
+  explicit PrerenderPLTRecorder(TabContents* tab_contents);
+  virtual ~PrerenderPLTRecorder();
+
+  // WebNavigationObserver implementation.
+  virtual bool OnMessageReceived(const IPC::Message& message);
+
+  // Message handler.
+  void OnDidStartProvisionalLoadForFrame(int64 frame_id,
+                                         bool main_frame,
+                                         const GURL& url);
+
+  virtual void DidStopLoading();
+
+ private:
+  TabContents* tab_contents_;
+
+  // System time at which the current load was started for the purpose of
+  // the perceived page load time (PPLT).
+  base::TimeTicks pplt_load_start_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrerenderPLTRecorder);
+};
+
+#endif  // CHROME_BROWSER_PRERENDER_PRERENDER_PLT_RECORDER_H_