content: convert zoom notifications to observer usage

content/browser/host_zoom_map_impl.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 CONTENT_BROWSER_HOST_ZOOM_MAP_IMPL_H_
 #define CONTENT_BROWSER_HOST_ZOOM_MAP_IMPL_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 16 matching lines @@
  public:
   HostZoomMapImpl();
   virtual ~HostZoomMapImpl();
 
   // HostZoomMap implementation:
   virtual void CopyFrom(HostZoomMap* copy) OVERRIDE;
   virtual double GetZoomLevel(const std::string& host) const OVERRIDE;
   virtual void SetZoomLevel(const std::string& host, double level) OVERRIDE;
   virtual double GetDefaultZoomLevel() const OVERRIDE;
   virtual void SetDefaultZoomLevel(double level) OVERRIDE;
+  virtual void AddZoomLevelChangedCallback(
+      const ZoomLevelChangedCallback& callback) OVERRIDE;
+  virtual void RemoveZoomLevelChangedCallback(
+      const ZoomLevelChangedCallback& callback) OVERRIDE;
 
   // Returns the temporary zoom level that's only valid for the lifetime of
   // the given WebContents (i.e. isn't saved and doesn't affect other
   // WebContentses) if it exists, the default zoom level otherwise.
   //
   // This may be called on any thread.
   double GetTemporaryZoomLevel(int render_process_id,
                                int render_view_id) const;
 
   // Sets the temporary zoom level that's only valid for the lifetime of this
   // WebContents.
   //
   // This should only be called on the UI thread.
   void SetTemporaryZoomLevel(int render_process_id,
                              int render_view_id,
                              double level);
 
   // NotificationObserver implementation.
   virtual void Observe(int type,
                        const NotificationSource& source,
                        const NotificationDetails& details) OVERRIDE;
 
  private:
   typedef std::map<std::string, double> HostZoomLevels;
 
+  // Callbacks called when zoom level changes.
+  std::vector<ZoomLevelChangedCallback> zoom_level_changed_callbacks_;
+
   // Copy of the pref data, so that we can read it on the IO thread.
   HostZoomLevels host_zoom_levels_;
   double default_zoom_level_;
 
   struct TemporaryZoomLevel {
     int render_process_id;
     int render_view_id;
     double zoom_level;
   };
 
   // Don't expect more than a couple of tabs that are using a temporary zoom
   // level, so vector is fine for now.
   std::vector<TemporaryZoomLevel> temporary_zoom_levels_;
 
   // Used around accesses to |host_zoom_levels_|, |default_zoom_level_| and
   // |temporary_zoom_levels_| to guarantee thread safety.
   mutable base::Lock lock_;
 
   NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(HostZoomMapImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_HOST_ZOOM_MAP_IMPL_H_