Add SessionStateObserver with ActiveUserChanged()

chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc

Index: chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc b/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
index 753cb86989e3d7101fa1d269a32b519493eb9884..7d1ec86b0b889f652fcbe6f9ae374263b7c46ba4 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
@@ -24,6 +24,7 @@
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/speech/tts_controller.h"
 #include "chrome/browser/ui/ash/caps_lock_delegate_chromeos.h"
+#include "chrome/browser/ui/ash/session_state_delegate_chromeos.h"
 #include "chrome/browser/ui/ash/window_positioner.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
@@ -186,6 +187,10 @@ ash::CapsLockDelegate* ChromeShellDelegate::CreateCapsLockDelegate() {
   return new CapsLockDelegate(xkeyboard);
 }
 
+ash::SessionStateDelegate* ChromeShellDelegate::CreateSessionStateDelegate() {
+  return new SessionStateDelegateChromeos;
+}
+
 void ChromeShellDelegate::ShowKeyboardOverlay() {
   // TODO(mazda): Move the show logic to ash (http://crbug.com/124222).
   Profile* profile = ProfileManager::GetDefaultProfileOrOffTheRecord();