Implement upgrade notifications....

chrome/browser/browser_shutdown.cc

Index: chrome/browser/browser_shutdown.cc
===================================================================
--- chrome/browser/browser_shutdown.cc	(revision 48146)
+++ chrome/browser/browser_shutdown.cc	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -28,6 +28,7 @@
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/common/chrome_paths.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/chrome_plugin_lib.h"
 #include "net/dns_global.h"
@@ -128,6 +129,14 @@
                       shutdown_num_processes_slow_);
   }
 
+  // Check local state for the restart flag so we can restart the session below.
+  bool restart_last_session = false;
+  if (prefs->HasPrefPath(prefs::kRestartLastSessionOnShutdown)) {
+    restart_last_session =
+        prefs->GetBoolean(prefs::kRestartLastSessionOnShutdown);
+    prefs->ClearPref(prefs::kRestartLastSessionOnShutdown);
+  }
+
   prefs->SavePersistentPrefs();
 
 #if defined(OS_WIN)
@@ -152,7 +161,21 @@
       shutdown_type_ != browser_shutdown::END_SESSION) {
     Upgrade::SwapNewChromeExeIfPresent();
   }
+
+  if (restart_last_session) {
+    // Make sure to relaunch the browser with the same command line and add
+    // Restore Last Session flag if session restore is not set.
+    CommandLine command_line = CommandLine::FromString(
+        CommandLine::ForCurrentProcess()->command_line_string());
+    if (!command_line.HasSwitch(switches::kRestoreLastSession))
+      command_line.AppendSwitch(switches::kRestoreLastSession);
+    Upgrade::RelaunchChromeBrowser(command_line);

[Nico, 2010/08/27 05:14:09]

Isn't this very racy? RelaunchChromeBrowser() mostly just calls
base::LaunchApp() directly, which means we're basically hope that the current
process finishes fast enough before the new process starts up.

[Nico, 2010/08/27 05:17:15]

This might be the cause for http://crbug.com/50803 and possibly
http://crbug.com/49631

+  }
 #endif
+#if !defined(OS_WIN)
+  if (restart_last_session)
+    NOTIMPLEMENTED();
+#endif
 
   if (shutdown_type_ > NOT_VALID && shutdown_num_processes_ > 0) {
     // Measure total shutdown time as late in the process as possible