Add UMA metrics for profile switching.

chrome/browser/ui/webui/signin/user_manager_screen_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/signin/user_manager_screen_handler.h"
 
 #include "base/bind.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/value_conversions.h"
@@ skipping 368 matching lines @@
 
   g_browser_process->profile_manager()->ScheduleProfileForDeletion(
       profile_path,
       base::Bind(&OpenNewWindowForProfile, desktop_type_));
   ProfileMetrics::LogProfileDeleteUser(
       ProfileMetrics::DELETE_PROFILE_USER_MANAGER);
 }
 
 void UserManagerScreenHandler::HandleLaunchGuest(const base::ListValue* args) {
   if (IsGuestModeEnabled()) {
-    ProfileMetrics::LogProfileSwitchUser(ProfileMetrics::SWITCH_PROFILE_GUEST);

[Mike Lerman, 2015/01/21 20:58:03]

Why did you remove this? It's definitely interesting to know how often the Guest
Profile was opened.

[anthonyvd, 2015/01/21 21:12:18]

We ended up logging it twice.  Once here and once in
profiles::SwitchToGuestProfile so I removed it here and all code paths that go
through SwitchToGuestProfile log it.

     profiles::SwitchToGuestProfile(
         desktop_type_,
         base::Bind(&UserManagerScreenHandler::OnSwitchToProfileComplete,
                    weak_ptr_factory_.GetWeakPtr()));
   } else {
     // The UI should have prevented the user from allowing the selection of
     // guest mode.
     NOTREACHED();
   }
 }
@@ skipping 358 matching lines @@
     Profile* profile, Profile::CreateStatus profile_create_status) {
   Browser* browser = chrome::FindAnyBrowser(profile, false, desktop_type_);
   if (browser && browser->window()) {
     OnBrowserWindowReady(browser);
   } else {
     registrar_.Add(this,
                    chrome::NOTIFICATION_BROWSER_WINDOW_READY,
                    content::NotificationService::AllSources());
   }
 }