cros: Use SessionController for lock starting code

ash/session/session_controller.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/session/session_controller.h"
 
 #include <algorithm>
 
 #include "ash/session/session_observer.h"
 #include "ash/shell.h"
@@ skipping 192 matching lines @@
   if (user_sessions_[0]->session_id != active_session_id_) {
     active_session_id_ = user_sessions_[0]->session_id;
 
     for (auto& observer : observers_)
       observer.OnActiveUserSessionChanged(user_sessions_[0]->account_id);
 
     UpdateLoginStatus();
   }
 }
 
+void SessionController::RunLockAnimation(
+    const RunLockAnimationCallback& callback) {
+  LockStateController* const lock_state_controller =
+      Shell::Get()->lock_state_controller();
+
+  lock_state_controller->SetLockScreenDisplayedCallback(callback);
+  lock_state_controller->OnStartingLock();
+}
+
 void SessionController::RunUnlockAnimation(
     const RunUnlockAnimationCallback& callback) {
   is_unlocking_ = true;
 
-  // Shell could have no instance in tests.

[James Cook, 2017/04/19 23:13:12]

Thanks for cleaning this up.

[xiyuan, 2017/04/20 18:23:59]

I have to put it back. SessionControllerTest derives directly from testing::Test
and has no Shell. :(

-  if (Shell::HasInstance())
-    Shell::Get()->lock_state_controller()->OnLockScreenHide(callback);
+  Shell::Get()->lock_state_controller()->OnLockScreenHide(callback);
 }
 
 void SessionController::NotifyChromeTerminating() {
   for (auto& observer : observers_)
     observer.OnChromeTerminating();
 }
 
 void SessionController::ClearUserSessionsForTest() {
   user_sessions_.clear();
 }
@@ skipping 99 matching lines @@
   const LoginStatus new_login_status = CalculateLoginStatus();
   if (new_login_status == login_status_)
     return;
 
   login_status_ = new_login_status;
   for (auto& observer : observers_)
     observer.OnLoginStatusChanged(login_status_);
 }
 
 }  // namespace ash