Add WebStateListOrderController to control WebState insertion.

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
index d3e38058e97f3328fe20710d12b1eec7d44714cc..caeb5b01046ae355a1e7b0ed67206bfaf8db1d2c 100644
--- a/ios/chrome/browser/tabs/tab_model_order_controller.h
+++ b/ios/chrome/browser/tabs/tab_model_order_controller.h
@@ -8,20 +8,6 @@
 #import <Foundation/Foundation.h>
 
 #import "ios/chrome/browser/tabs/tab_model.h"
-#include "ui/base/page_transition_types.h"
-
-namespace TabModelOrderConstants {
-
-// 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
@@ -32,17 +18,6 @@ enum InsertionAdjacency {
 // Initializer, |model| must be non-nil and is not retained.
 - (instancetype)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.
-- (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;