content: convert zoom notifications to observer usage

chrome/browser/ui/gtk/browser_toolbar_gtk.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_GTK_BROWSER_TOOLBAR_GTK_H_
 #define CHROME_BROWSER_UI_GTK_BROWSER_TOOLBAR_GTK_H_
 
 #include <gtk/gtk.h>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/public/pref_member.h"
 #include "chrome/browser/command_observer.h"
 #include "chrome/browser/ui/gtk/custom_button.h"
 #include "chrome/browser/ui/gtk/menu_gtk.h"
 #include "chrome/browser/ui/toolbar/wrench_menu_model.h"
+#include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/gtk/gtk_signal.h"
 #include "ui/base/gtk/gtk_signal_registrar.h"
 #include "ui/base/gtk/owned_widget_gtk.h"
 #include "ui/base/models/simple_menu_model.h"
 
 class BackForwardButtonGtk;
 class Browser;
@@ skipping 77 matching lines @@
                        const content::NotificationDetails& details) OVERRIDE;
 
   // Whether the wrench/hotdogs menu is currently visible to the user.
   bool IsWrenchMenuShowing() const;
 
   // Message that we should react to a state change.
   void UpdateWebContents(content::WebContents* contents,
                          bool should_restore_state);
 
  private:
+  void OnZoomLevelChanged(const std::string& host);
+
   // Connect/Disconnect signals for dragging a url onto the home button.
   void SetUpDragForHomeButton();
 
   // Sets the top corners of the toolbar to rounded, or sets them to normal,
   // depending on the state of the browser window. Returns false if no action
   // was taken (the roundedness was already correct), true otherwise.
   bool UpdateRoundedness();
 
   // Gtk callback for the "expose-event" signal.
   // The alignment contains the toolbar.
@@ skipping 79 matching lines @@
   Browser* browser_;
   BrowserWindowGtk* window_;
 
   // Controls whether or not a home button should be shown on the toolbar.
   BooleanPrefMember show_home_button_;
 
   // Preferences controlling the configured home page.
   StringPrefMember home_page_;
   BooleanPrefMember home_page_is_new_tab_page_;
 
+  content::HostZoomMap::ZoomLevelChangedCallback zoom_callback_;
   content::NotificationRegistrar registrar_;
 
   // A GtkEntry that isn't part of the hierarchy. We keep this for native
   // rendering.
   ui::OwnedWidgetGtk offscreen_entry_;
 
   // Manages the home button drop signal handler.
   scoped_ptr<ui::GtkSignalRegistrar> drop_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserToolbarGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_BROWSER_TOOLBAR_GTK_H_