Move the notion of current Tab from TabModel to WebStateList.

ios/chrome/browser/tabs/tab_model_order_controller.h

Index: ios/chrome/browser/tabs/tab_model_order_controller.h
diff --git a/ios/chrome/browser/tabs/tab_model_order_controller.h b/ios/chrome/browser/tabs/tab_model_order_controller.h
deleted file mode 100644
index caeb5b01046ae355a1e7b0ed67206bfaf8db1d2c..0000000000000000000000000000000000000000
--- a/ios/chrome/browser/tabs/tab_model_order_controller.h
+++ /dev/null
@@ -1,27 +0,0 @@
-// 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_TABS_TAB_MODEL_ORDER_CONTROLLER_H_
-#define IOS_CHROME_BROWSER_TABS_TAB_MODEL_ORDER_CONTROLLER_H_
-
-#import <Foundation/Foundation.h>
-
-#import "ios/chrome/browser/tabs/tab_model.h"
-
-// An object that allows different types of ordering and reselection to be
-// heuristics plugged into a TabStripModel. Closely parallels
-// chrome/browser/tabs/tab_strip_model_order_controller.h
-// but without the dependence on TabContentsWrapper and TabStripModel.
-@interface TabModelOrderController : NSObject
-
-// Initializer, |model| must be non-nil and is not retained.
-- (instancetype)initWithTabModel:(TabModel*)model;
-
-// Returns the tab in which to shift selection after a tab is closed. May
-// return nil if there are no more tabs.
-- (Tab*)determineNewSelectedTabFromRemovedTab:(Tab*)removedTab;
-
-@end
-
-#endif  // IOS_CHROME_BROWSER_TABS_TAB_MODEL_ORDER_CONTROLLER_H_