Abstract content::SessionStorageNamespace from core TabRestore code

chrome/browser/sessions/chrome_tab_restore_service_client.h

 // Copyright 2015 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 CHROME_BROWSER_SESSIONS_CHROME_TAB_RESTORE_SERVICE_CLIENT_H_
 #define CHROME_BROWSER_SESSIONS_CHROME_TAB_RESTORE_SERVICE_CLIENT_H_
 
 #include "base/basictypes.h"
 #include "components/sessions/core/tab_restore_service_client.h"
 
@@ skipping 12 matching lines @@
       int host_desktop_type,
       const std::string& app_name) override;
   TabRestoreServiceDelegate* FindTabRestoreServiceDelegateForWebContents(
       const content::WebContents* contents) override;
   TabRestoreServiceDelegate* FindTabRestoreServiceDelegateWithID(
       SessionID::id_type desired_id,
       int host_desktop_type) override;
   bool ShouldTrackURLForRestore(const GURL& url) override;
   std::string GetExtensionAppIDForWebContents(
       content::WebContents* web_contents) override;
+  scoped_ptr<sessions::TabClientData> GetTabClientDataForWebContents(
+      content::WebContents* web_contents) override;
   base::SequencedWorkerPool* GetBlockingPool() override;
   base::FilePath GetPathToSaveTo() override;
   GURL GetNewTabURL() override;
   bool HasLastSession() override;
   void GetLastSession(const sessions::GetLastSessionCallback& callback,
                       base::CancelableTaskTracker* tracker) override;
   void OnTabRestored(const GURL& url) override;
 
   Profile* profile_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeTabRestoreServiceClient);
 };
 
 #endif  // CHROME_BROWSER_SESSIONS_CHROME_TAB_RESTORE_SERVICE_CLIENT_H_