Add unittests checking that old saved session can be restored.

ios/chrome/browser/tabs/tab_model_unittest.mm

 // 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.
 
 #import <objc/runtime.h>
 
 #include "base/files/file_path.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
@@ skipping 23 matching lines @@
 #import "ios/web/web_state/ui/crw_web_controller.h"
 #import "ios/web/web_state/web_state_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 #import "third_party/ocmock/OCMock/OCMock.h"
 #include "third_party/ocmock/gtest_support.h"
 
 using web::WebStateImpl;
 
-// 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.
-// We could expose this as part of the service's public API, but again that
-// might encourage use where we don't want it. As a result, just use the
-// known private-for-testing method directly.
-@interface SessionServiceIOS (Testing)
-- (void)performSaveWindow:(SessionWindowIOS*)window
-              toDirectory:(NSString*)directory;
-@end
 
 @interface TabModel (VisibleForTesting)
 - (SessionWindowIOS*)windowForSavingSession;
 @end
 
 // Defines a TabModelObserver for use in unittests.  This class can be used to
 // test if an observer method was called or not.
 @interface TabModelObserverPong : NSObject<TabModelObserver> {
   // TODO(crbug.com/661989): Add tests for the other observer methods.
   BOOL tabMovedWasCalled_;
@@ skipping 1092 matching lines @@
             [tab_model_ openerOfTab:[tab_model_ tabAtIndex:2]]);
   EXPECT_EQ([tab_model_ tabAtIndex:2],
             [tab_model_ openerOfTab:[tab_model_ tabAtIndex:0]]);
 
   // Clean up.
   EXPECT_TRUE([[NSFileManager defaultManager] removeItemAtPath:stashPath
                                                          error:nullptr]);
 }
 
 }  // anonymous namespace