Add metrics to keep track of the tab activate/deactivate cycle

chrome/browser/extensions/api/tabs/tabs_event_router.h

 // Copyright 2013 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_EXTENSIONS_API_TABS_TABS_EVENT_ROUTER_H_
 #define CHROME_BROWSER_EXTENSIONS_API_TABS_TABS_EVENT_ROUTER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 36 matching lines @@
   explicit TabsEventRouter(Profile* profile);
   ~TabsEventRouter() override;
 
   // BrowserTabStripTrackerDelegate:
   bool ShouldTrackBrowser(Browser* browser) override;
 
   // chrome::BrowserListObserver:
   void OnBrowserSetLastActive(Browser* browser) override;
 
   // TabStripModelObserver:
-  void TabInsertedAt(content::WebContents* contents,
+  void TabInsertedAt(TabStripModel* tab_strip_model,
+                     content::WebContents* contents,
                      int index,
                      bool active) override;
   void TabClosingAt(TabStripModel* tab_strip_model,
                     content::WebContents* contents,
                     int index) override;
   void TabDetachedAt(content::WebContents* contents, int index) override;
   void ActiveTabChanged(content::WebContents* old_contents,
                         content::WebContents* new_contents,
                         int index,
                         int reason) override;
   void TabSelectionChanged(TabStripModel* tab_strip_model,
                            const ui::ListSelectionModel& old_model) override;
   void TabMoved(content::WebContents* contents,
                 int from_index,
                 int to_index) override;
   void TabChangedAt(content::WebContents* contents,
                     int index,
                     TabChangeType change_type) override;
   void TabReplacedAt(TabStripModel* tab_strip_model,
                      content::WebContents* old_contents,
                      content::WebContents* new_contents,
                      int index) override;
-  void TabPinnedStateChanged(content::WebContents* contents,
+  void TabPinnedStateChanged(TabStripModel* tab_strip_model,
+                             content::WebContents* contents,
                              int index) override;
 
   // ZoomObserver:
   void OnZoomChanged(
       const zoom::ZoomController::ZoomChangedEventData& data) override;
 
   // favicon::FaviconDriverObserver:
   void OnFaviconUpdated(favicon::FaviconDriver* favicon_driver,
                         NotificationIconType notification_icon_type,
                         const GURL& icon_url,
@@ skipping 116 matching lines @@
 
   ScopedObserver<memory::TabManager, TabsEventRouter>
       tab_manager_scoped_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TabsEventRouter);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_TABS_TABS_EVENT_ROUTER_H_