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

chrome/browser/tab_contents/tab_contents.h

Index: chrome/browser/tab_contents/tab_contents.h
===================================================================
--- chrome/browser/tab_contents/tab_contents.h	(revision 72357)
+++ chrome/browser/tab_contents/tab_contents.h	(working copy)
@@ -68,6 +68,7 @@
 class PluginInstallerInfoBarDelegate;
 class Profile;
 class PrerenderManager;
+class PrerenderPLTRecorder;
 struct RendererPreferences;
 class RenderViewHost;
 class SessionStorageNamespace;
@@ -1124,6 +1125,9 @@
   // PluginInstallerInfoBarDelegate, lazily created.
   scoped_ptr<PluginInstallerInfoBarDelegate> plugin_installer_;
 
+  // Prerender PageLoadTime Recorder.
+  scoped_ptr<PrerenderPLTRecorder> prerender_plt_recorder_;
+
   // TabContentsSSLHelper, lazily created.
   scoped_ptr<TabContentsSSLHelper> ssl_helper_;