Move session length timer into tray bubble.

ash/system/tray/system_tray.cc

Index: ash/system/tray/system_tray.cc
diff --git a/ash/system/tray/system_tray.cc b/ash/system/tray/system_tray.cc
index d8ac9a539b725728c8e5676d2f14fc7e1607c18d..a68bd1e0bc4b5d807a5613daefaeff9f65c35f7a 100644
--- a/ash/system/tray/system_tray.cc
+++ b/ash/system/tray/system_tray.cc
@@ -153,9 +153,6 @@ void SystemTray::InitializeTrayItems(SystemTrayDelegate* delegate) {
 }
 
 void SystemTray::CreateItems(SystemTrayDelegate* delegate) {
-#if defined(OS_CHROMEOS)
-  AddTrayItem(new TraySessionLengthLimit(this));
-#endif
 #if !defined(OS_WIN)
   // Create user items for each possible user.
   ash::Shell* shell = ash::Shell::GetInstance();
@@ -175,6 +172,7 @@ void SystemTray::CreateItems(SystemTrayDelegate* delegate) {
   tray_date_ = new TrayDate(this);
 
 #if defined(OS_CHROMEOS)
+  AddTrayItem(new TraySessionLengthLimit(this));
   AddTrayItem(new TrayEnterprise(this));
   AddTrayItem(new TrayLocallyManagedUser(this));
   AddTrayItem(new TrayIME(this));