Revert 267174 "Revert of Multiprofile: switch to newly added use..."

> Revert of Multiprofile: switch to newly added user to the session (https://codereview.chromium.org/246253009/)
> 
> Reason for revert:
> Suspecting this change as a root cause for superflaky UserAddingScreenTest.AddingSeveralUsers
> 
> See http://crbug.com/368621
> 
> Original issue's description:
> > Multiprofile: switch to newly added user to the session
> > 
> > This CL remember pending user switch and do it as soon as profile
> > ready. From UI perspective this look very smooth because profile loading
> > is actually fast so previous desktop is not shown. But if it will be
> > a problem on slow device we may need to stay on add user screen a bit longer.
> > 
> > BUG=333879
> > TEST=manual
> > R=nkostylev@chromium.org
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=266239
> 
> TBR=dpolukhin@chromium.org,dpolukhin@google.com
> NOTREECHECKS=true
> NOTRY=true
> BUG=333879,368621
> 
> Review URL: https://codereview.chromium.org/257393003

TBR=nkostylev@chromium.org

Review URL: https://codereview.chromium.org/267463002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267197 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 22 insertions, 14 deletions

diff --git a/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc b/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
index b6e4e8e..04e60ce 100644
--- a/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
+++ b/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
@@ -915,9 +915,6 @@ class MultiProfileFileManagerBrowserTest : public FileManagerBrowserTestBase {
     const TestAccountInfo& info = kTestAccounts[PRIMARY_ACCOUNT_INDEX];
 
     AddUser(info, true);
-    chromeos::UserManager* const user_manager = chromeos::UserManager::Get();
-    if (user_manager->GetActiveUser() != user_manager->FindUser(info.email))
-      chromeos::UserManager::Get()->SwitchActiveUser(info.email);
     FileManagerBrowserTestBase::SetUpOnMainThread();
   }
 
diff --git a/chrome/browser/chromeos/login/user_manager_impl.cc b/chrome/browser/chromeos/login/user_manager_impl.cc
index 9fcd332..7f27162 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.cc
+++ b/chrome/browser/chromeos/login/user_manager_impl.cc
@@ -424,9 +424,9 @@ void UserManagerImpl::UserLoggedIn(const std::string& user_id,
     lru_logged_in_users_.push_back(user);
     // Reset the new user flag if the user already exists.
     is_current_user_new_ = false;
-    // Set active user wallpaper back.
-    WallpaperManager::Get()->SetUserWallpaperNow(active_user_->email());
     NotifyUserAddedToSession(user);
+    // Remember that we need to switch to this user as soon as profile ready.
+    pending_user_switch_ = user_id;
     return;
   }
 
@@ -971,7 +971,18 @@ void UserManagerImpl::Observe(int type,
       User* user = GetUserByProfile(profile);
       if (user != NULL)
         user->set_profile_is_created();
-
+      // If there is pending user switch, do it now.
+      if (!pending_user_switch_.empty()) {
+        // Call SwitchActiveUser async because otherwise it may cause
+        // ProfileManager::GetProfile before the profile gets registered
+        // in ProfileManager. It happens in case of sync profile load when
+        // NOTIFICATION_PROFILE_CREATED is called synchronously.
+        base::MessageLoop::current()->PostTask(FROM_HERE,
+          base::Bind(&UserManagerImpl::SwitchActiveUser,
+                     base::Unretained(this),
+                     pending_user_switch_));
+        pending_user_switch_.clear();
+      }
       break;
     }
     default:
diff --git a/chrome/browser/chromeos/login/user_manager_impl.h b/chrome/browser/chromeos/login/user_manager_impl.h
index ef63d1a..1ec2c2e 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.h
+++ b/chrome/browser/chromeos/login/user_manager_impl.h
@@ -483,6 +483,10 @@ class UserManagerImpl
   scoped_ptr<policy::CloudExternalDataPolicyObserver>
       wallpaper_policy_observer_;
 
+  // ID of the user just added to the session that needs to be activated
+  // as soon as user's profile is loaded.
+  std::string pending_user_switch_;
+
   DISALLOW_COPY_AND_ASSIGN(UserManagerImpl);
 };
 
diff --git a/chrome/browser/chromeos/preferences_browsertest.cc b/chrome/browser/chromeos/preferences_browsertest.cc
index fe3fb00..b8a5267 100644
--- a/chrome/browser/chromeos/preferences_browsertest.cc
+++ b/chrome/browser/chromeos/preferences_browsertest.cc
@@ -153,19 +153,15 @@ IN_PROC_BROWSER_TEST_F(PreferencesTest, MultiProfiles) {
   // Add second user and init its prefs with different values.
   UserAddingScreen::Get()->Start();
   content::RunAllPendingInMessageLoop();
+  DisableAnimations();
   AddUser(kTestUsers[1]);
-  EXPECT_TRUE(user1->is_active());
+  content::RunAllPendingInMessageLoop();
   const User* user2 = user_manager->FindUser(kTestUsers[1]);
+  EXPECT_TRUE(user2->is_active());
   PrefService* prefs2 = user_manager->GetProfileByUser(user2)->GetPrefs();
   SetPrefs(prefs2, true);
 
-  // First user is still active, so settings was not changed.
-  EXPECT_TRUE(user1->is_active());
-  CheckSettingsCorrespondToPrefs(prefs1);
-
-  // Switch user and check that settings was changed accordingly.
-  DisableAnimations();
-  user_manager->SwitchActiveUser(kTestUsers[1]);
+  // Check that settings were changed accordingly.
   EXPECT_TRUE(user2->is_active());
   CheckSettingsCorrespondToPrefs(prefs2);