Record the number of loaded profiles when a profile is erased from the profiles map kept by profile

chrome/browser/profiles/profile_manager.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/profiles/profile_manager.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 931 matching lines @@
 
   // Perform initialization.
   if (success) {
     DoFinalInit(profile, go_off_the_record);
     if (go_off_the_record)
       profile = profile->GetOffTheRecordProfile();
     info->created = true;
   } else {
     profile = NULL;
     profiles_info_.erase(iter);
+    // TODO(yiyaoliu): This is temporary, remove it after it's not used.
+    UMA_HISTOGRAM_COUNTS_100("UMA.ProfilesCount.AfterErase",
+                             profiles_info_.size());
   }
 
   if (profile) {
     // If this was the guest profile, finish setting its special status.
     if (profile->GetPath() == ProfileManager::GetGuestProfilePath())
       SetGuestProfilePrefs(profile);
 
     // Invoke CREATED callback for incognito profiles.
     if (go_off_the_record)
       RunCallbacks(callbacks, profile, Profile::CREATE_STATUS_CREATED);
@@ skipping 350 matching lines @@
           last_non_supervised_profile_path.BaseName().MaybeAsASCII());
       FinishDeletingProfile(profile_to_delete_path);
     }
   }
 }
 #endif
 
 ProfileManagerWithoutInit::ProfileManagerWithoutInit(
     const base::FilePath& user_data_dir) : ProfileManager(user_data_dir) {
 }