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

chrome/browser/ui/tabs/tab_strip_model.cc

 // 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.
 
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <string>
@@ skipping 302 matching lines @@
   const web_modal::WebContentsModalDialogManager* manager =
       web_modal::WebContentsModalDialogManager::FromWebContents(contents);
   if (manager)
     data->set_blocked(manager->IsDialogActive());
 
   contents_data_.insert(contents_data_.begin() + index, data);
 
   selection_model_.IncrementFrom(index);
 
   FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
-                    TabInsertedAt(contents, index, active));
+                    TabInsertedAt(this, contents, index, active));
   if (active) {
     ui::ListSelectionModel new_model;
     new_model.Copy(selection_model_);
     new_model.SetSelectedIndex(index);
     SetSelection(new_model, NOTIFY_DEFAULT);
   }
 }
 
 WebContents* TabStripModel::ReplaceWebContentsAt(int index,
                                                  WebContents* new_contents) {
@@ skipping 317 matching lines @@
   contents_data_[index]->set_pinned(pinned);
   if (pinned && index != non_pinned_tab_index) {
     MoveWebContentsAtImpl(index, non_pinned_tab_index, false);
     index = non_pinned_tab_index;
   } else if (!pinned && index + 1 != non_pinned_tab_index) {
     MoveWebContentsAtImpl(index, non_pinned_tab_index - 1, false);
     index = non_pinned_tab_index - 1;
   }
 
   FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
-                    TabPinnedStateChanged(contents_data_[index]->web_contents(),
-                                          index));
+                    TabPinnedStateChanged(
+                        this, contents_data_[index]->web_contents(), index));
 }
 
 bool TabStripModel::IsTabPinned(int index) const {
   DCHECK(ContainsIndex(index));
   return contents_data_[index]->pinned();
 }
 
 bool TabStripModel::IsTabBlocked(int index) const {
   return contents_data_[index]->blocked();
 }
@@ skipping 692 matching lines @@
 
 void TabStripModel::FixOpenersAndGroupsReferencing(int index) {
   WebContents* old_contents = GetWebContentsAtImpl(index);
   for (WebContentsData* data : contents_data_) {
     if (data->group() == old_contents)
       data->set_group(contents_data_[index]->group());
     if (data->opener() == old_contents)
       data->set_opener(contents_data_[index]->opener());
   }
 }