content: convert zoom notifications to observer usage

chrome/browser/ui/toolbar/wrench_menu_model.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_TOOLBAR_WRENCH_MENU_MODEL_H_
 #define CHROME_BROWSER_UI_TOOLBAR_WRENCH_MENU_MODEL_H_
 
 #include "base/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
@@ skipping 95 matching lines @@
   virtual void ActiveTabChanged(content::WebContents* old_contents,
                                 content::WebContents* new_contents,
                                 int index,
                                 bool user_gesture) OVERRIDE;
   virtual void TabReplacedAt(TabStripModel* tab_strip_model,
                              content::WebContents* old_contents,
                              content::WebContents* new_contents,
                              int index) OVERRIDE;
   virtual void TabStripModelDeleted() OVERRIDE;
 
+  void OnZoomLevelChanged(const std::string& host);
+
   // Overridden from content::NotificationObserver:
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // Getters.
   Browser* browser() const { return browser_; }
 
   BookmarkSubMenuModel* bookmark_sub_menu_model() const {
     return bookmark_sub_menu_model_.get();
@@ skipping 48 matching lines @@
 
   Browser* browser_;  // weak
   TabStripModel* tab_strip_model_; // weak
 
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(WrenchMenuModel);
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_WRENCH_MENU_MODEL_H_