Upstream Chrome on iOS source code [2/11].

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 reciever.
+- (instancetype)initForReadingWithData:(NSData*)data
+                          browserState:(ios::ChromeBrowserState*)browserState;
+
+@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
+
+#endif  // IOS_CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_