Add SessionStateObserver with ActiveUserChanged()

ash/test/test_session_state_delegate.cc

Index: ash/test/test_session_state_delegate.cc
diff --git a/ash/test/test_session_state_delegate.cc b/ash/test/test_session_state_delegate.cc
index 22fdfacda994ee3569bbefad2d88d9a05a348543..1fdfef62945ee9a42eedcb03ce9b938ad341b102 100644
--- a/ash/test/test_session_state_delegate.cc
+++ b/ash/test/test_session_state_delegate.cc
@@ -88,13 +88,20 @@ const gfx::ImageSkia& TestSessionStateDelegate::GetUserImage(
   return null_image_;
 }
 
-void TestSessionStateDelegate::GetLoggedInUsers(UserEmailList* users) {
+void TestSessionStateDelegate::GetLoggedInUsers(UserIdList* users) {
 }
 
 void TestSessionStateDelegate::SwitchActiveUser(const std::string& email) {
   activated_user_ = email;
 }
 
+void TestSessionStateDelegate::AddSessionStateObserver(
+    ash::SessionStateObserver* observer) {
+}
+
+void TestSessionStateDelegate::RemoveSessionStateObserver(
+    ash::SessionStateObserver* observer) {
+}
 
 }  // namespace test
 }  // namespace ash