Revert of [ios] Move WebStateList to ios/chrome/browser/web_state_list.

ios/shared/chrome/browser/tabs/web_state_list.h

Index: ios/shared/chrome/browser/tabs/web_state_list.h
diff --git a/ios/shared/chrome/browser/tabs/web_state_list.h b/ios/shared/chrome/browser/tabs/web_state_list.h
new file mode 100644
index 0000000000000000000000000000000000000000..4038cd76465ca4c50c4ee39e45d545296b302663
--- /dev/null
+++ b/ios/shared/chrome/browser/tabs/web_state_list.h
@@ -0,0 +1,162 @@
+// 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>
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/observer_list.h"
+#include "ui/base/page_transition_types.h"
+
+class WebStateListDelegate;
+class WebStateListObserver;
+class WebStateListOrderController;
+struct WebStateOpener;
+
+namespace web {
+class WebState;
+}
+
+// Manages a list of WebStates.
+class WebStateList {
+ public:
+  explicit WebStateList(WebStateListDelegate* delegate);
+  ~WebStateList();
+
+  // Returns whether the model is empty or not.
+  bool empty() const { return web_state_wrappers_.empty(); }
+
+  // Returns the number of WebStates in the model.
+  int count() const { return static_cast<int>(web_state_wrappers_.size()); }
+
+  // Returns the index of the currently active WebState, or kInvalidIndex if
+  // there are no active WebState.
+  int active_index() const { return active_index_; }
+
+  // Returns true if the specified index is contained by the model.
+  bool ContainsIndex(int index) const;
+
+  // Returns the currently active WebState or null if there is none.
+  web::WebState* GetActiveWebState() 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;
+
+  // Returns information about the opener of the WebState at the specified
+  // index. The structure |opener| will be null if there is no opener.
+  WebStateOpener GetOpenerOfWebStateAt(int index) const;
+
+  // Stores information about the opener of the WebState at the specified
+  // index. The WebStateOpener |opener| must be non-null and the WebState
+  // must be in WebStateList.
+  void SetOpenerOfWebStateAt(int index, WebStateOpener 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.
+  void InsertWebState(int index, std::unique_ptr<web::WebState> web_state);
+
+  // Inserts the specified WebState at the best position in the WebStateList
+  // given the specified transition, opener, etc. It defaults to inserting the
+  // WebState at the end of the list.
+  void AppendWebState(ui::PageTransition transition,
+                      std::unique_ptr<web::WebState> web_state,
+                      WebStateOpener 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).
+  std::unique_ptr<web::WebState> ReplaceWebStateAt(
+      int index,
+      std::unique_ptr<web::WebState> web_state);
+
+  // Detaches the WebState at the specified index. Returns the detached WebState
+  // to the caller (abandon ownership of the returned WebState).
+  std::unique_ptr<web::WebState> DetachWebStateAt(int index);
+
+  // Closes and destroys the WebState at the specified index.
+  void CloseWebStateAt(int index);
+
+  // Closes and destroys all WebStates.
+  void CloseAllWebStates();
+
+  // Makes the WebState at the specified index the active WebState.
+  void ActivateWebStateAt(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:
+  class WebStateWrapper;
+
+  // Sets the opener of any WebState that reference the WebState at the
+  // specified index to null.
+  void ClearOpenersReferencing(int index);
+
+  // Notify the observers if the active WebState change.
+  void NotifyIfActiveWebStateChanged(web::WebState* old_web_state,
+                                     bool user_action);
+
+  // 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;
+
+  // The WebStateList delegate.
+  WebStateListDelegate* delegate_;
+
+  // Wrappers to the WebStates hosted by the WebStateList.
+  std::vector<std::unique_ptr<WebStateWrapper>> web_state_wrappers_;
+
+  // An object that determines where new WebState should be inserted and where
+  // selection should move when a WebState is detached.
+  std::unique_ptr<WebStateListOrderController> order_controller_;
+
+  // List of observers notified of changes to the model.
+  base::ObserverList<WebStateListObserver, true> observers_;
+
+  // Index of the currently active WebState, kInvalidIndex if no such WebState.
+  int active_index_ = kInvalidIndex;
+
+  DISALLOW_COPY_AND_ASSIGN(WebStateList);
+};
+
+#endif  // IOS_SHARED_CHROME_BROWSER_TABS_WEB_STATE_LIST_H_