Revert of [ios] Switches ToolbarModelDelegateIOS to use WebStateList.

ios/chrome/browser/ui/toolbar/toolbar_model_delegate_ios.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_UI_TOOLBAR_TOOLBAR_MODEL_DELEGATE_IOS_H_
 #define IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_MODEL_DELEGATE_IOS_H_
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/macros.h"
 #include "components/toolbar/toolbar_model_delegate.h"
 
-class WebStateList;
+@class Tab;
+@class TabModel;
 
 namespace web {
 class NavigationItem;
-class WebState;
 }
 
 // Implementation of ToolbarModelDelegate which uses an instance of
 // TabModel in order to fulfil its duties.
 class ToolbarModelDelegateIOS : public ToolbarModelDelegate {
  public:
-  // |web_state_list| must outlive this ToolbarModelDelegateIOS object.
-  explicit ToolbarModelDelegateIOS(WebStateList* web_state_list);
+  explicit ToolbarModelDelegateIOS(TabModel* tab_model);
   ~ToolbarModelDelegateIOS() override;
 
-  // Returns the active WebState.
-  web::WebState* GetActiveWebState() const;
+  // Sets the |tab_model_| with provided values.
+  void SetTabModel(TabModel* tab_model);
+
+  // Returns the current tab.
+  Tab* GetCurrentTab() const;
 
  private:
   // Helper method to extract the NavigationItem from which the states are
   // retrieved. If this returns null (which can happens during initialization),
   // default values are used.
   web::NavigationItem* GetNavigationItem() const;
 
   // ToolbarModelDelegate implementation:
   base::string16 FormattedStringWithEquivalentMeaning(
       const GURL& url,
       const base::string16& formatted_url) const override;
   bool GetURL(GURL* url) const override;
   bool ShouldDisplayURL() const override;
   SecurityLevel GetSecurityLevel() const override;
   scoped_refptr<net::X509Certificate> GetCertificate() const override;
   bool FailsMalwareCheck() const override;
   const gfx::VectorIcon* GetVectorIconOverride() const override;
 
-  WebStateList* web_state_list_;  // weak
+  base::scoped_nsobject<TabModel> tab_model_;
 
   DISALLOW_COPY_AND_ASSIGN(ToolbarModelDelegateIOS);
 };
 
 #endif  // IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_MODEL_DELEGATE_IOS_H_