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

chrome/browser/tab_contents/tab_contents.h

 // 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_TAB_CONTENTS_TAB_CONTENTS_H_
 #define CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 1148 matching lines @@
 
   // Indicates the largest PageID we've seen.  This field is ignored if we are
   // a TabContents, in which case the max page ID is stored separately with
   // each SiteInstance.
   // TODO(brettw) this seems like it can be removed according to the comment.
   int32 max_page_id_;
 
   // System time at which the current load was started.
   base::TimeTicks current_load_start_;
 
+  // System time at which the current load was started for the purpose of
+  // the perceived page load time (PPLT).
+  base::TimeTicks pplt_load_start_;
+
   // The current load state and the URL associated with it.
   net::LoadState load_state_;
   string16 load_state_host_;
   // Upload progress, for displaying in the status bar.
   // Set to zero when there is no significant upload happening.
   uint64 upload_size_;
   uint64 upload_position_;
 
   // Data for current page -----------------------------------------------------
 
@@ skipping 156 matching lines @@
   ObserverList<WebNavigationObserver> web_navigation_observers_;
 
   // Content restrictions, used to disable print/copy etc based on content's
   // (full-page plugins for now only) permissions.
   int content_restrictions_;
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_