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

chrome/browser/ui/cocoa/tabs/tab_strip_model_observer_bridge.h

 // Copyright (c) 2012 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_UI_COCOA_TABS_TAB_STRIP_MODEL_OBSERVER_BRIDGE_H_
 #define CHROME_BROWSER_UI_COCOA_TABS_TAB_STRIP_MODEL_OBSERVER_BRIDGE_H_
 
 #import <Foundation/Foundation.h>
 
 #include "base/compiler_specific.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 
 class TabStripModel;
 
 namespace content {
 class WebContents;
 }
 
 // A C++ bridge class to handle receiving notifications from the C++ tab strip
 // model. When the caller allocates a bridge, it automatically registers for
 // notifications from |model| and passes messages to |controller| via the
 // informal protocol below. The owner of this object is responsible for deleting
 // it (and thus unhooking notifications) before |controller| is destroyed.
 class TabStripModelObserverBridge : public TabStripModelObserver {
  public:
   TabStripModelObserverBridge(TabStripModel* model, id controller);
   ~TabStripModelObserverBridge() override;
 
   // Overridden from TabStripModelObserver
-  void TabInsertedAt(content::WebContents* contents,
+  void TabInsertedAt(TabStripModel* tab_strip_model,
+                     content::WebContents* contents,
                      int index,
                      bool foreground) override;
   void TabClosingAt(TabStripModel* tab_strip_model,
                     content::WebContents* contents,
                     int index) override;
   void TabDetachedAt(content::WebContents* contents, int index) override;
   void TabDeactivated(content::WebContents* contents) 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;
   void TabStripEmpty() override;
 
  private:
   id controller_;  // weak, owns me
   TabStripModel* model_;  // weak, owned by Browser
 };
 
 // A collection of methods which can be selectively implemented by any
 // Cocoa object to receive updates about changes to a tab strip model. It is
@@ skipping 20 matching lines @@
 - (void)tabReplacedWithContents:(content::WebContents*)newContents
                previousContents:(content::WebContents*)oldContents
                         atIndex:(NSInteger)index;
 - (void)tabPinnedStateChangedWithContents:(content::WebContents*)contents
                                   atIndex:(NSInteger)index;
 - (void)tabStripEmpty;
 - (void)tabSelectionChanged;
 @end
 
 #endif  // CHROME_BROWSER_UI_COCOA_TABS_TAB_STRIP_MODEL_OBSERVER_BRIDGE_H_