[ios] Cleanup SessionServiceIOS implementation.

ios/chrome/browser/sessions/session_service.h

-// Copyright 2012 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 IOS_CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_
-#define IOS_CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_
-
-#import <Foundation/Foundation.h>
-
-#include "base/mac/scoped_nsobject.h"
-
-namespace ios {
-class ChromeBrowserState;
-}
-
-@class SessionWindowIOS;
-
-// Trivial NSKeyedUnarchiver subclass that can be configured with a
-// ChromeBrowserState instance that decoding classes can use.
-@interface SessionWindowUnarchiver : NSKeyedUnarchiver
-
-// The BrowserState set on the unarchiver at init; a weak pointer.
-@property(nonatomic, readonly) ios::ChromeBrowserState* browserState;
-
-// Inits exactly as initForReadingWithData: does, additionally setting
-// |browserState| on the receiver.
-- (instancetype)initForReadingWithData:(NSData*)data
-                          browserState:(ios::ChromeBrowserState*)browserState
-    NS_DESIGNATED_INITIALIZER;
-
-@end
-
-// A singleton service for saving the current session. Can either save on a
-// delay or immediately. Saving is always performed on a separate thread.
-@interface SessionServiceIOS : NSObject
-
-// Lazily creates a singleton instance. Use this instead of calling alloc/init.
-+ (SessionServiceIOS*)sharedService;
-
-// Saves the session represented by |window| to the given browserState directory
-// on disk. If |immediately| is NO, the save is done after a delay. If another
-// call is pending, this one is ignored. If YES, the save is done now,
-// cancelling any pending calls.  Either way, the save is done on a separate
-// thread to avoid blocking the UI thread. As a result, |window| should contain
-// copies of non-threadsafe objects.
-- (void)saveWindow:(SessionWindowIOS*)window
-    forBrowserState:(ios::ChromeBrowserState*)browserState
-        immediately:(BOOL)immediately;
-
-// Loads the window from the given browserState directory on disk on the main
-// thread. Returns nil if no session was previously saved.
-- (SessionWindowIOS*)loadWindowForBrowserState:
-    (ios::ChromeBrowserState*)browserState;
-
-// Schedules deletion of the file containing the commands for the last session
-// in the given browserState directory.
-- (void)deleteLastSession:(NSString*)directory;
-
-// Loads the window from the given backup file on disk on the main thread.
-// Returns nil if unable to read the sessions.
-- (SessionWindowIOS*)loadWindowFromPath:(NSString*)path
-                        forBrowserState:(ios::ChromeBrowserState*)browserState;
-
-// Returns the path of the session file.
-- (NSString*)sessionFilePathForDirectory:(NSString*)directory;
-
-@end
-
-@interface SessionServiceIOS (Testing)
-
-// For some of the unit tests, we need to make sure the session is saved
-// immediately so we can read it back in to verify various attributes. This
-// is not a situation we normally expect to be in because we never
-// want the session being saved on the main thread in the production app.
-- (void)performSaveWindow:(SessionWindowIOS*)window
-              toDirectory:(NSString*)directory;
-
-@end
-
-#endif  // IOS_CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_