Re-reland: chromeos: Fix shelf appearing at login screen under mash

chrome/browser/ui/ash/session_controller_client.cc

 // Copyright 2016 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/ash/session_controller_client.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "ash/public/cpp/session_types.h"
@@ skipping 16 matching lines @@
 #include "services/service_manager/public/cpp/connector.h"
 #include "ui/base/resource/resource_bundle.h"
 
 using session_manager::SessionManager;
 using user_manager::UserManager;
 using user_manager::User;
 using user_manager::UserList;
 
 namespace {
 
+SessionControllerClient* g_instance = nullptr;
+
 uint32_t GetSessionId(const User* user) {
   const UserList logged_in_users = UserManager::Get()->GetLoggedInUsers();
   // TODO(xiyuan): Update with real session id when user session tracking
   //     code is moved from UserManager to SessionManager.
   for (size_t i = 0; i < logged_in_users.size(); ++i) {
     if (logged_in_users[i] == user)
       return i + 1;
   }
 
   NOTREACHED();
@@ skipping 29 matching lines @@
 }  // namespace
 
 SessionControllerClient::SessionControllerClient() : binding_(this) {
   SessionManager::Get()->AddObserver(this);
   UserManager::Get()->AddSessionStateObserver(this);
 
   ConnectToSessionControllerAndSetClient();
   SendSessionInfoIfChanged();
   // User sessions and their order will be sent via UserSessionStateObserver
   // even for crash-n-restart.
+
+  DCHECK(!g_instance);
+  g_instance = this;
 }
 
 SessionControllerClient::~SessionControllerClient() {
+  DCHECK_EQ(this, g_instance);
+  g_instance = nullptr;
+
   SessionManager::Get()->RemoveObserver(this);
   UserManager::Get()->RemoveSessionStateObserver(this);
 }
 
 void SessionControllerClient::RequestLockScreen() {
   DoLockScreen();
 }
 
 void SessionControllerClient::SwitchActiveUser(
     const std::string& serialized_account_id) {
@@ skipping 119 matching lines @@
       account_id = (*it)->GetAccountId();
   } else {
     if (it == logged_in_users.begin())
       it = logged_in_users.end();
     account_id = (*(--it))->GetAccountId();
   }
 
   DoSwitchActiveUser(account_id);
 }
 
+// static
+void SessionControllerClient::FlushForTesting() {
+  g_instance->session_controller_.FlushForTesting();
+}
+
 void SessionControllerClient::OnSessionStateChanged() {
   SendSessionInfoIfChanged();
 }
 
 void SessionControllerClient::ConnectToSessionControllerAndSetClient() {
   content::ServiceManagerConnection::GetForProcess()
       ->GetConnector()
       ->BindInterface(ash_util::GetAshServiceName(), &session_controller_);
 
   // Set as |session_controller_|'s client.
@@ skipping 23 matching lines @@
 void SessionControllerClient::SendUserSessionOrder() {
   UserManager* const user_manager = UserManager::Get();
 
   const UserList logged_in_users = user_manager->GetLoggedInUsers();
   std::vector<uint32_t> user_session_ids;
   for (auto* user : user_manager->GetLRULoggedInUsers())
     user_session_ids.push_back(GetSessionId(user));
 
   session_controller_->SetUserSessionOrder(user_session_ids);
 }