Tests covering additional screens of reset-Rollback option added.

chromeos/dbus/fake_update_engine_client.cc

Index: chromeos/dbus/fake_update_engine_client.cc
diff --git a/chromeos/dbus/fake_update_engine_client.cc b/chromeos/dbus/fake_update_engine_client.cc
index 76a21492e10fbff98835bc2bf0b78899d2b26fcd..f7f7e544d20bac34964bb33addc47fefdbc42066 100644
--- a/chromeos/dbus/fake_update_engine_client.cc
+++ b/chromeos/dbus/fake_update_engine_client.cc
@@ -21,9 +21,11 @@ void FakeUpdateEngineClient::Init(dbus::Bus* bus) {
 }
 
 void FakeUpdateEngineClient::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
 }
 
 void FakeUpdateEngineClient::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
 }
 
 bool FakeUpdateEngineClient::HasObserver(Observer* observer) {
@@ -55,6 +57,7 @@ UpdateEngineClient::Status FakeUpdateEngineClient::GetLastStatus() {
 
   UpdateEngineClient::Status last_status = status_queue_.front();
   status_queue_.pop();
+  FOR_EACH_OBSERVER(Observer, observers_, UpdateStatusChanged(last_status));

[Daniel Erat, 2014/05/06 14:49:00]

this shouldn't be triggered by GetLastStatus() -- the real UpdateEngineClient
implementation just returns a cached status here.

please add a NotifyObserversThatStatusChanged() method that tests can call to
FakeUpdateEngineClient instead.

   return last_status;
 }