Add SessionStateObserver with ActiveUserChanged()

ash/test/test_session_state_delegate.h

Index: ash/test/test_session_state_delegate.h
diff --git a/ash/test/test_session_state_delegate.h b/ash/test/test_session_state_delegate.h
index 83944d4c74b54f3eaa3751fef98c2ddaa908c38a..6882dc88ea5bffc28d90f2a102361e30bda92fa2 100644
--- a/ash/test/test_session_state_delegate.h
+++ b/ash/test/test_session_state_delegate.h
@@ -37,6 +37,10 @@ class TestSessionStateDelegate : public SessionStateDelegate {
       ash::MultiProfileIndex index) const OVERRIDE;
   virtual void GetLoggedInUsers(UserEmailList* users) OVERRIDE;
   virtual void SwitchActiveUser(const std::string& email) OVERRIDE;
+  virtual void AddSessionStateObserver(
+      ash::SessionStateObserver* observer) OVERRIDE;
+  virtual void RemoveSessionStateObserver(
+      ash::SessionStateObserver* observer) OVERRIDE;
 
   // Updates the internal state that indicates whether a session is in progress
   // and there is an active user. If |has_active_user| is |false|,