Add BackgroundModeOptimizer that can restart the browser

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 54df3f5641ce39e4442445d9eab7d90651824854..887c629b7b68bfb8583a89f0114c33cffb427560 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -232,6 +232,10 @@
 #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"
@@ -2014,11 +2018,19 @@ void ChromeBrowserMainParts::PostDestroyThreads() {
   // 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();