mash: Move //ash/session to //ash/common/session

ash/common/session/session_state_observer.cc

 // Copyright 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.
 
-#include "ash/session/session_state_observer.h"
+#include "ash/common/session/session_state_observer.h"
 
-#include "ash/session/session_state_delegate.h"
-#include "ash/shell.h"
+#include "ash/common/session/session_state_delegate.h"
+#include "ash/common/wm_shell.h"
 
 namespace ash {
 
 ScopedSessionStateObserver::ScopedSessionStateObserver(
-    ash::SessionStateObserver* observer)
+    SessionStateObserver* observer)
     : observer_(observer) {
-  ash::Shell::GetInstance()->session_state_delegate()->AddSessionStateObserver(
+  WmShell::Get()->GetSessionStateDelegate()->AddSessionStateObserver(observer_);
+}
+
+ScopedSessionStateObserver::~ScopedSessionStateObserver() {
+  WmShell::Get()->GetSessionStateDelegate()->RemoveSessionStateObserver(
       observer_);
 }
 
-ScopedSessionStateObserver::~ScopedSessionStateObserver() {
-  ash::Shell::GetInstance()
-      ->session_state_delegate()
-      ->RemoveSessionStateObserver(observer_);
-}
-
 }  // namespace ash