Switch TabContentsSyncedTabDelegate to use WebContentsUserData.

chrome/browser/sync/glue/synced_tab_delegate.h

 // Copyright (c) 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 CHROME_BROWSER_SYNC_GLUE_SYNCED_TAB_DELEGATE_H__
 #define CHROME_BROWSER_SYNC_GLUE_SYNCED_TAB_DELEGATE_H__
 
 #include <string>
 
 #include "chrome/browser/sessions/session_id.h"
 
 class Profile;
 
 namespace content {
 class NavigationEntry;
 }
 
 namespace browser_sync {
 
 // A SyncedTabDelegate is used to insulate the sync code from depending
-// directly on WebContents, TabContents and NavigationController.
+// directly on WebContents, NavigationController, and the extensions TabHelper.
 class SyncedTabDelegate {
  public:
   virtual ~SyncedTabDelegate() {}
 
-  // Method from TabContents.
+  // Methods from TabContents.
 
   virtual SessionID::id_type GetWindowId() const = 0;
   virtual SessionID::id_type GetSessionId() const = 0;
   virtual bool IsBeingDestroyed() const = 0;
   virtual Profile* profile() const = 0;
 
-  // Method derived from TabContents.
+  // Method derived from extensions TabHelper.
 
   virtual std::string GetExtensionAppId() const = 0;
 
-  // Method from NavigationController
+  // Methods from NavigationController.
 
   virtual int GetCurrentEntryIndex() const = 0;
   virtual int GetEntryCount() const = 0;
   virtual int GetPendingEntryIndex() const = 0;
   virtual content::NavigationEntry* GetPendingEntry() const = 0;
   virtual content::NavigationEntry* GetEntryAtIndex(int i) const = 0;
   virtual content::NavigationEntry* GetActiveEntry() const = 0;
 
   virtual bool IsPinned() const = 0;
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNCED_TAB_DELEGATE_H__