mash: Run pre-unlock animation via SessionController

ash/common/session/session_state_observer.h

 // Copyright (c) 2013 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.
 
 #ifndef ASH_COMMON_SESSION_SESSION_STATE_OBSERVER_H_
 #define ASH_COMMON_SESSION_SESSION_STATE_OBSERVER_H_
 
 #include "ash/ash_export.h"
 #include "base/macros.h"
 #include "components/session_manager/session_manager_types.h"
@@ skipping 14 matching lines @@
 
   // Called when a user session is updated, such as avatar change.
   virtual void UserSessionUpdated(const AccountId& account_id) {}
 
   // Called when the session state is changed.
   virtual void SessionStateChanged(session_manager::SessionState state) {}
 
   // Called when the login status is changed. |login_status| is the new status.
   virtual void LoginStatusChanged(LoginStatus login_status) {}
 
+  // Called when the lock state is changed. |locked| is the current lock stated.
+  virtual void OnLockStateChanged(bool locked) {}

[James Cook, 2017/04/07 20:26:55]

nit: Can this be LockStateChanged() to match the others? Or maybe the others
should be renamed to On*Changed (in a separate CL)?

[xiyuan, 2017/04/07 21:50:01]

Changed to LockStateChanged().

I will do the rename to On*Changed in a separate CL.

+
  protected:
   virtual ~SessionStateObserver() {}
 };
 
 // A class to attach / detach an object as a session state observer.
 class ASH_EXPORT ScopedSessionStateObserver {
  public:
   explicit ScopedSessionStateObserver(SessionStateObserver* observer);
   virtual ~ScopedSessionStateObserver();
 
  private:
   ash::SessionStateObserver* observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedSessionStateObserver);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SESSION_SESSION_STATE_OBSERVER_H_