Add opener-opened relationship between WebState in WebStateList.

ios/shared/chrome/browser/tabs/web_state_list.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_SHARED_CHROME_BROWSER_TABS_WEB_STATE_LIST_H_
 #define IOS_SHARED_CHROME_BROWSER_TABS_WEB_STATE_LIST_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 29 matching lines @@
   bool ContainsIndex(int index) const;
 
   // Returns the WebState at the specified index. It is invalid to call this
   // with an index such that |ContainsIndex(index)| returns false.
   web::WebState* GetWebStateAt(int index) const;
 
   // Returns the index of the specified WebState or kInvalidIndex if the
   // WebState is not in the model.
   int GetIndexOfWebState(const web::WebState* web_state) const;
 
-  // Inserts the specified WebState at the specified index.
-  void InsertWebState(int index, web::WebState* web_state);
+  // Returns the WebState that opened the WebState at the specified index or
+  // null if there is no opener on record.
+  web::WebState* GetOpenerOfWebStateAt(int index) const;
+
+  // Sets the opener for WebState at the specified index. The |opener| must be
+  // in the WebStateList.
+  void SetOpenerOfWebStateAt(int index, web::WebState* opener);
+
+  // Returns the index of the next WebState in the sequence of WebStates opened
+  // from the specified WebState after |start_index|, or kInvalidIndex if there
+  // are no such WebState. If |use_group| is true, the opener's navigation index
+  // is used to detect navigation changes within the same session.
+  int GetIndexOfNextWebStateOpenedBy(const web::WebState* opener,
+                                     int start_index,
+                                     bool use_group) const;
+
+  // Returns the index of the last WebState in the sequence of WebStates opened
+  // from the specified WebState after |start_index|, or kInvalidIndex if there
+  // are no such WebState. If |use_group| is true, the opener's navigation index
+  // is used to detect navigation changes within the same session.
+  int GetIndexOfLastWebStateOpenedBy(const web::WebState* opener,
+                                     int start_index,
+                                     bool use_group) const;
+
+  // Inserts the specified WebState at the specified index with an optional
+  // opener (null if there is no opener).
+  void InsertWebState(int index,
+                      web::WebState* web_state,
+                      web::WebState* opener);
 
   // Moves the WebState at the specified index to another index.
   void MoveWebStateAt(int from_index, int to_index);
 
   // Replaces the WebState at the specified index with new WebState. Returns
   // the old WebState at that index to the caller (abandon ownership of the
-  // returned WebState).
-  web::WebState* ReplaceWebStateAt(int index, web::WebState* web_state);
+  // returned WebState). An optional opener for the new WebState may be passed.
+  web::WebState* ReplaceWebStateAt(int index,
+                                   web::WebState* web_state,
+                                   web::WebState* opener);
 
   // Detaches the WebState at the specified index.
   void DetachWebStateAt(int index);
 
   // Adds an observer to the model.
   void AddObserver(WebStateListObserver* observer);
 
   // Removes an observer from the model.
   void RemoveObserver(WebStateListObserver* observer);
 
   // Invalid index.
   static const int kInvalidIndex = -1;
 
  private:
+  // Sets the opener of any WebState that reference the WebState at the
+  // specified index to null.
+  void FixOpenersReferencing(int index);
+
+  // Returns the index of the |n|-th WebState (with n > 0) in the sequence of
+  // WebStates opened from the specified WebState after |start_index|, or
+  // kInvalidIndex if there are no such WebState. If |use_group| is true, the
+  // opener's navigation index is used to detect navigation changes within the
+  // same session.
+  int GetIndexOfNthWebStateOpenedBy(const web::WebState* opener,
+                                    int start_index,
+                                    bool use_group,
+                                    int n) const;
+
   class WebStateWrapper;
   const WebStateOwnership web_state_ownership_;
   std::vector<std::unique_ptr<WebStateWrapper>> web_state_wrappers_;
 
   // List of observers notified of changes to the model.
   base::ObserverList<WebStateListObserver, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(WebStateList);
 };
 
 #endif  // IOS_SHARED_CHROME_BROWSER_TABS_WEB_STATE_LIST_H_