Revert 255617, due to it not tracking use of the link doctor page properly.

chrome/browser/ui/navigation_correction_tab_observer.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_UI_NAVIGATION_CORRECTION_TAB_OBSERVER_H_
-#define CHROME_BROWSER_UI_NAVIGATION_CORRECTION_TAB_OBSERVER_H_
-
-#include "base/prefs/pref_change_registrar.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-#include "content/public/browser/web_contents_observer.h"
-#include "content/public/browser/web_contents_user_data.h"
-
-class Profile;
-
-namespace user_prefs {
-class PrefRegistrySyncable;
-}
-
-// Per-tab class to implement navigation suggestion service functionality.
-class NavigationCorrectionTabObserver
-    : public content::WebContentsObserver,
-      public content::NotificationObserver,
-      public content::WebContentsUserData<NavigationCorrectionTabObserver> {
- public:
-  virtual ~NavigationCorrectionTabObserver();
-
-  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
-
- private:
-  explicit NavigationCorrectionTabObserver(content::WebContents* web_contents);
-  friend class content::WebContentsUserData<NavigationCorrectionTabObserver>;
-
-  // content::WebContentsObserver overrides:
-  virtual void RenderViewCreated(
-      content::RenderViewHost* render_view_host) OVERRIDE;
-
-  // content::NotificationObserver overrides:
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
-  // Internal helpers ----------------------------------------------------------
-
-  // Returns the URL for the correction service.  If the returned URL
-  // is empty, the default error pages will be used.
-  GURL GetNavigationCorrectionURL() const;
-
-  // Called when navigation corrections are enabled or disabled.
-  void OnEnabledChanged();
-
-  // Updates the renderer's navigation correction service configuration.
-  void UpdateNavigationCorrectionInfo(content::RenderViewHost* rvh);
-
-  Profile* profile_;
-  content::NotificationRegistrar registrar_;
-  PrefChangeRegistrar pref_change_registrar_;
-
-  DISALLOW_COPY_AND_ASSIGN(NavigationCorrectionTabObserver);
-};
-
-#endif  // CHROME_BROWSER_UI_NAVIGATION_CORRECTION_TAB_OBSERVER_H_