Add BackgroundModeOptimizer that can restart the browser

chrome/browser/browser_shutdown.cc

Index: chrome/browser/browser_shutdown.cc
diff --git a/chrome/browser/browser_shutdown.cc b/chrome/browser/browser_shutdown.cc
index ab8f9d7561797948661f840a633e867733a84666..73f77b2c95e5a26afa5d929ee0fedefade1e86b2 100644
--- a/chrome/browser/browser_shutdown.cc
+++ b/chrome/browser/browser_shutdown.cc
@@ -194,7 +194,8 @@ bool ShutdownPreThreadsStop() {
   return restart_last_session;
 }
 
-void ShutdownPostThreadsStop(bool restart_last_session) {
+void ShutdownPostThreadsStop(bool restart_last_session,
+                             bool restart_in_background) {
   delete g_browser_process;
   g_browser_process = NULL;
 
@@ -239,6 +240,8 @@ void ShutdownPostThreadsStop(bool restart_last_session) {
       else
         new_cl->AppendSwitch(it.first);
     }
+    if (restart_in_background)
+      new_cl->AppendSwitch(switches::kNoStartupWindow);
 
 #if defined(OS_POSIX) || defined(OS_WIN)
     upgrade_util::RelaunchChromeBrowser(*new_cl.get());