chromeos: Move files in //ash/common to //ash, part 1

ash/system/session/session_length_limit_observer.h

Index: ash/system/session/session_length_limit_observer.h
diff --git a/ash/common/system/chromeos/session/session_length_limit_observer.h b/ash/system/session/session_length_limit_observer.h
similarity index 71%
rename from ash/common/system/chromeos/session/session_length_limit_observer.h
rename to ash/system/session/session_length_limit_observer.h
index d46a25373eddf80808eb91b4ba602b5a806a8ffe..610feb41002eb1504efce6fa983b7b4c880c648a 100644
--- a/ash/common/system/chromeos/session/session_length_limit_observer.h
+++ b/ash/system/session/session_length_limit_observer.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef ASH_COMMON_SYSTEM_CHROMEOS_SESSION_SESSION_LENGTH_LIMIT_OBSERVER_H_
-#define ASH_COMMON_SYSTEM_CHROMEOS_SESSION_SESSION_LENGTH_LIMIT_OBSERVER_H_
+#ifndef ASH_SYSTEM_SESSION_SESSION_LENGTH_LIMIT_OBSERVER_H_
+#define ASH_SYSTEM_SESSION_SESSION_LENGTH_LIMIT_OBSERVER_H_
 
 #include "ash/ash_export.h"
 
@@ -23,4 +23,4 @@ class ASH_EXPORT SessionLengthLimitObserver {
 
 }  // namespace ash
 
-#endif  // ASH_COMMON_SYSTEM_CHROMEOS_SESSION_SESSION_LENGTH_LIMIT_OBSERVER_H_
+#endif  // ASH_SYSTEM_SESSION_SESSION_LENGTH_LIMIT_OBSERVER_H_