Add histograms that track how long it takes to open the new tab page.

chrome/browser/tab_contents/tab_contents.h

 // Copyright (c) 2009 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_
 
 #include "build/build_config.h"
 
 #include <map>
@@ skipping 599 matching lines @@
   }
 
   RendererPreferences* GetMutableRendererPrefs() {
     return &renderer_preferences_;
   }
 
   void set_opener_dom_ui_type(DOMUITypeID opener_dom_ui_type) {
     opener_dom_ui_type_ = opener_dom_ui_type;
   }
 
+  // We want to time how long it takes to create a new tab page.  This method
+  // gets called as parts of the new tab page have loaded.
+  void LogNewTabTime(const std::string& event_name);
+
+  // Set the time when we started to create the new tab page.  This time is
+  // from before we created this TabContents.
+  void set_new_tab_start_time(const base::TimeTicks& time) {
+    new_tab_start_time_ = time;
+  }
+
  private:
   friend class NavigationController;
   // Used to access the child_windows_ (ConstrainedWindowList) for testing
   // automation purposes.
   friend class AutomationProvider;
   friend class BlockedPopupContainerTest;
   friend class BlockedPopupContainerControllerTest;
 
   FRIEND_TEST(BlockedPopupContainerTest, TestReposition);
   FRIEND_TEST(TabContentsTest, NoJSMessageOnInterstitials);
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   // have never used the monibox for search before.
   scoped_ptr<OmniboxSearchHint> omnibox_search_hint_;
 
   // Settings that get passed to the renderer process.
   RendererPreferences renderer_preferences_;
 
   // If this tab was created from a renderer using window.open, this will be
   // non-NULL and represent the DOMUI of the opening renderer.
   DOMUITypeID opener_dom_ui_type_;
 
+  // The time that we started to create the new tab page.
+  base::TimeTicks new_tab_start_time_;
+
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_