[ios] Active web state observer in tab collection.

ios/clean/chrome/browser/ui/tab_collection/tab_collection_view_controller.h

 // Copyright 2017 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_CLEAN_CHROME_BROWSER_UI_TAB_COLLECTION_TAB_COLLECTION_VIEW_CONTROLLER_H_
 #define IOS_CLEAN_CHROME_BROWSER_UI_TAB_COLLECTION_TAB_COLLECTION_VIEW_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
 
 #import "ios/clean/chrome/browser/ui/tab_collection/tab_collection_consumer.h"
 
-@protocol TabCollectionDataSource;
-
 // Controller for a scrolling view displaying square cells that represent
 // the user's open tabs.
 @interface TabCollectionViewController
     : UIViewController<TabCollectionConsumer, UICollectionViewDataSource>
 // A collection view of tabs.
 @property(nonatomic, weak, readonly) UICollectionView* tabs;
 // Model for collection view.
 @property(nonatomic, strong, readonly)
     NSMutableArray<TabCollectionItem*>* items;
+// Selected index of tab collection.
+@property(nonatomic, assign) int selectedIndex;

[marq (ping after 24h), 2017/06/02 11:31:00]

Does this need to be public? The consumer protocol provides a setter for it.

[edchin, 2017/06/02 17:24:59]

Done.

 @end
 
 #endif  // IOS_CLEAN_CHROME_BROWSER_UI_TAB_COLLECTION_TAB_COLLECTION_VIEW_CONTROLLER_H_