Write "logout-started" event on next boot.

chrome/common/pref_names.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/common/pref_names.h"
 
 #include "base/basictypes.h"
 #include "chrome/common/pref_font_webkit_names.h"
 
 namespace prefs {
@@ skipping 2053 matching lines @@
 // A dictionary containing server-provided device state pulled form the cloud
 // after recovery.
 const char kServerBackedDeviceState[] = "server_backed_device_state";
 
 // Customized wallpaper URL, which is already downloaded and scaled.
 // The URL from this preference must never be fetched. It is compared to the
 // URL from customization document to check if wallpaper URL has changed
 // since wallpaper was cached.
 const char kCustomizationDefaultWallpaperURL[] =
     "customization.default_wallpaper_url";
+
+// System uptime, when last logout started.
+// This is cleared after reboot.

[stevenjb, 2014/05/30 16:20:23]

nit: One line?

[Alexander Alekseev, 2014/05/30 21:12:45]

I've updated comment, so now it doesn't fit into a single line.

+const char kLogoutStartedLast[] = "chromeos.logout-started";
 #endif
 
 // Whether there is a Flash version installed that supports clearing LSO data.
 const char kClearPluginLSODataEnabled[] = "browser.clear_lso_data_enabled";
 
 // Whether we should show Pepper Flash-specific settings.
 const char kPepperFlashSettingsEnabled[] =
     "browser.pepper_flash_settings_enabled";
 
 // String which specifies where to store the disk cache.
@@ skipping 421 matching lines @@
 // "mapped_title" entries, detailing the bookmark target URL (if any), the title
 // given by the PartnerBookmarksProvider and either the user-visible renamed
 // title or an empty string if the bookmark node was removed.
 const char kPartnerBookmarkMappings[] = "partnerbookmarks.mappings";
 #endif
 
 // Whether DNS Quick Check is disabled in proxy resolution.
 const char kQuickCheckEnabled[] = "proxy.quick_check_enabled";
 
 }  // namespace prefs