chromeos: makes WindowManager not delete shell when connection to mus is lost

chrome/browser/ui/ash/ash_init.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/ash/ash_init.h"
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/accelerators/accelerator_controller_delegate_aura.h"
 #include "ash/accessibility_types.h"
 #include "ash/aura/shell_port_classic.h"
@@ skipping 49 matching lines @@
   shell_init_params.blocking_pool = content::BrowserThread::GetBlockingPool();
 
   ash::Shell::CreateInstance(shell_init_params);
 }
 
 std::unique_ptr<ash::mus::WindowManager> CreateMusShell() {
   service_manager::Connector* connector =
       content::ServiceManagerConnection::GetForProcess()->GetConnector();
   std::unique_ptr<ash::mus::WindowManager> window_manager =
       base::MakeUnique<ash::mus::WindowManager>(connector, ash::Config::MUS);
+  // The WindowManager normally deletes the Shell when it loses its connection
+  // to mus. Disable that by installing an empty callback. Chrome installs
+  // its own callback to detect when the connection to mus is lost and that is
+  // what shuts everything down.
+  window_manager->SetLostConnectionCallback(base::BindOnce(&base::DoNothing));
   std::unique_ptr<aura::WindowTreeClient> window_tree_client =
       base::MakeUnique<aura::WindowTreeClient>(connector, window_manager.get(),
                                                window_manager.get());
   window_tree_client->ConnectAsWindowManager();
   aura::Env::GetInstance()->SetWindowTreeClient(window_tree_client.get());
   window_manager->Init(std::move(window_tree_client),
                        content::BrowserThread::GetBlockingPool(),
                        base::MakeUnique<ChromeShellDelegate>());
   CHECK(window_manager->WaitForInitialDisplays());
   return window_manager;
@@ skipping 72 matching lines @@
   ash::Shell::GetPrimaryRootWindow()->GetHost()->Show();
 }
 
 AshInit::~AshInit() {
   // |window_manager_| deletes the Shell.
   if (!window_manager_ && ash::Shell::HasInstance()) {
     ash::Shell::DeleteInstance();
     ash::ShellContentState::DestroyInstance();
   }
 }