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

ios/chrome/browser/tabs/tab_model_order_controller.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_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"
+#include "ui/base/page_transition_types.h"
+
+namespace TabModelOrderConstants {
+
+// InsertionPolicy is a general policy for opening all new tabs.
+enum InsertionPolicy {
+  // Newly created tabs are created after the selection. This is the default.
+  kInsertAfter,
+  // Newly created tabs are inserted before the selection.
+  kInsertBefore,
+};
+
+// InsertionAdjacency allows different links to choose to open tabs directly
+// before or after a given tab, depending on context.
+enum InsertionAdjacency {
+  // Insert a card just before (to the left of) a given card.
+  kAdjacentBefore,
+  // Insert a card just after (to the right of) a given card.
+  kAdjacentAfter,
+};
+
+}  // namespace TabModelOrderConstants
+
+// 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 {
+ @private
+  TabModel* model_;  // weak, owns us
+  TabModelOrderConstants::InsertionPolicy insertionPolicy_;
+}
+
+// Sets the insertion policy for new tabs. Default is |kInsertAfter|.
+@property(nonatomic, assign)
+    TabModelOrderConstants::InsertionPolicy insertionPolicy;
+
+// Initializer, |model| must be non-nil and is not retained.
+- (id)initWithTabModel:(TabModel*)model;
+
+// Determines where to place a newly opened tab by using the transition and
+// adjacency flags.
+- (NSUInteger)insertionIndexForTab:(Tab*)newTab
+                        transition:(ui::PageTransition)transition
+                            opener:(Tab*)parentTab
+                         adjacency:(TabModelOrderConstants::InsertionAdjacency)
+                                       adjacency;
+
+// Returns the index at which to append tabs, based on |insertionPolicy|.
+- (NSUInteger)insertionIndexForAppending;
+
+// 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_