Add BackgroundModeOptimizer that can restart the browser

chrome/browser/chrome_browser_main.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/chrome_browser_main.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <set>
@@ skipping 214 matching lines @@
 
 #if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
 #include "chrome/browser/first_run/upgrade_util.h"
 #endif
 
 #if !defined(DISABLE_NACL)
 #include "chrome/browser/component_updater/pnacl_component_installer.h"
 #include "components/nacl/browser/nacl_process_host.h"
 #endif  // !defined(DISABLE_NACL)
 
+#if BUILDFLAG(ENABLE_BACKGROUND)
+#include "chrome/browser/background/background_mode_manager.h"
+#endif  // BUILDFLAG(ENABLE_BACKGROUND)
+
 #if defined(ENABLE_EXTENSIONS)
 #include "chrome/browser/extensions/startup_helper.h"
 #include "extensions/browser/extension_protocols.h"
 #include "extensions/common/features/feature_provider.h"
 #include "extensions/components/javascript_dialog_extensions_client/javascript_dialog_extension_client_impl.h"
 #endif  // defined(ENABLE_EXTENSIONS)
 
 #if defined(ENABLE_PRINT_PREVIEW) && !defined(OFFICIAL_BUILD)
 #include "printing/printed_document.h"
 #endif  // defined(ENABLE_PRINT_PREVIEW) && !defined(OFFICIAL_BUILD)
@@ skipping 1762 matching lines @@
 #endif  // defined(SYZYASAN)
 #endif  // defined(OS_ANDROID)
 }
 
 void ChromeBrowserMainParts::PostDestroyThreads() {
 #if defined(OS_ANDROID)
   // On Android, there is no quit/exit. So the browser's main message loop will
   // not finish.
   NOTREACHED();
 #else
+
+  bool restart_in_background = false;
+
+#if BUILDFLAG(ENABLE_BACKGROUND)
+  restart_in_background = BackgroundModeManager::ShouldRestartInBackground();

[sky, 2016/07/06 16:55:33]

Doesn't this only matter if restart_last_session_?

[dgn, 2016/07/22 15:18:09]

Yes, made that explicit here.

+#endif  // BUILDFLAG(ENABLE_BACKGROUND)
+
   browser_process_->PostDestroyThreads();
   // browser_shutdown takes care of deleting browser_process, so we need to
   // release it.
   ignore_result(browser_process_.release());
-  browser_shutdown::ShutdownPostThreadsStop(restart_last_session_);
+  browser_shutdown::ShutdownPostThreadsStop(restart_last_session_,
+                                            restart_in_background);
   master_prefs_.reset();
   process_singleton_.reset();
   device_event_log::Shutdown();
 
   // We need to do this check as late as possible, but due to modularity, this
   // may be the last point in Chrome.  This would be more effective if done at
   // a higher level on the stack, so that it is impossible for an early return
   // to bypass this code.  Perhaps we need a *final* hook that is called on all
   // paths from content/browser/browser_main.
   CHECK(metrics::MetricsService::UmaMetricsProperlyShutdown());
 
 #if defined(OS_CHROMEOS)
   chromeos::CrosSettings::Shutdown();
 #endif  // defined(OS_CHROMEOS)
 #endif  // defined(OS_ANDROID)
 }
 
 // Public members:
 
 void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
   chrome_extra_parts_.push_back(parts);
 }