content: convert zoom notifications to observer usage

chrome/browser/ui/gtk/browser_toolbar_gtk.cc

 // 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.
 
 #include "chrome/browser/ui/gtk/browser_toolbar_gtk.h"
 
 #include <gdk/gdkkeysyms.h>
 #include <gtk/gtk.h>
 #include <X11/XF86keysym.h>
 
@@ skipping 223 matching lines @@
   GtkWidget* wrench_box = gtk_alignment_new(0, 0, 1, 1);
   g_signal_connect_after(wrench_box, "expose-event",
                          G_CALLBACK(OnWrenchMenuButtonExposeThunk), this);
   gtk_container_add(GTK_CONTAINER(wrench_box), wrench_button);
   gtk_box_pack_start(GTK_BOX(toolbar_), wrench_box, FALSE, FALSE, 4);
 
   wrench_menu_.reset(new MenuGtk(this, wrench_menu_model_.get()));
   // The bookmark menu model needs to be able to force the wrench menu to close.
   wrench_menu_model_->bookmark_sub_menu_model()->SetMenuGtk(wrench_menu_.get());
 
-  registrar_.Add(this, content::NOTIFICATION_ZOOM_LEVEL_CHANGED,
-      content::Source<HostZoomMap>(
-          HostZoomMap::GetForBrowserContext(profile)));
+  content::HostZoomMap::Observer::Observe(
+      HostZoomMap::GetForBrowserContext(profile));
 
   if (ShouldOnlyShowLocation()) {
     gtk_widget_show(event_box_);
     gtk_widget_show(alignment_);
     gtk_widget_show(toolbar_);
     gtk_widget_show_all(location_hbox_);
     gtk_widget_hide(reload_->widget());
   } else {
     gtk_widget_show_all(event_box_);
     if (actions_toolbar_->button_count() == 0)
@@ skipping 108 matching lines @@
     int id,
     ui::Accelerator* out_accelerator) {
   const ui::Accelerator* accelerator =
       AcceleratorsGtk::GetInstance()->GetPrimaryAcceleratorForCommand(id);
   if (!accelerator)
     return false;
   *out_accelerator = *accelerator;
   return true;
 }
 
+// content::HostZoomMap::Observer ----------------------------------------------
+
+void BrowserToolbarGtk::OnZoomLevelChanged(const std::string& host) {
+  // Since BrowserToolbarGtk create a new |wrench_menu_model_| in
+  // RebuildWrenchMenu(), the ordering of the observers of HostZoomMap
+  // can change, and result in subtle bugs like http://crbug.com/118823.
+  // Rather than depending on the ordering of the observers, always update
+  // the WrenchMenuModel before updating the WrenchMenu.
+  wrench_menu_model_->UpdateZoomControls();
+
+  // If our zoom level changed, we need to tell the menu to update its state,
+  // since the menu could still be open.
+  wrench_menu_->UpdateMenu();
+}
+
 // content::NotificationObserver -----------------------------------------------
 
 void BrowserToolbarGtk::Observe(int type,
                                 const content::NotificationSource& source,
                                 const content::NotificationDetails& details) {
   if (type == chrome::NOTIFICATION_BROWSER_THEME_CHANGED) {
     // Update the spacing around the menu buttons
     bool use_gtk = theme_service_->UsingNativeTheme();
     int border = use_gtk ? 0 : 2;
     gtk_container_set_border_width(
@@ skipping 24 matching lines @@
           theme_service_->GetRTLEnabledPixbufNamed(IDR_TOOLS));
     }
 
     UpdateRoundedness();
   } else if (type == chrome::NOTIFICATION_UPGRADE_RECOMMENDED) {
     // Redraw the wrench menu to update the badge.
     gtk_widget_queue_draw(wrench_menu_button_->widget());
   } else if (type == chrome::NOTIFICATION_GLOBAL_ERRORS_CHANGED) {
     is_wrench_menu_model_valid_ = false;
     gtk_widget_queue_draw(wrench_menu_button_->widget());
-  } else if (type == content::NOTIFICATION_ZOOM_LEVEL_CHANGED) {
-    // Since BrowserToolbarGtk create a new |wrench_menu_model_| in
-    // RebuildWrenchMenu(), the ordering of the observers of
-    // NOTIFICATION_ZOOM_LEVEL_CHANGED can change, and result in subtle bugs
-    // like http://crbug.com/118823. Rather than depending on the ordering
-    // of the notification observers, always update the WrenchMenuModel before
-    // updating the WrenchMenu.
-    wrench_menu_model_->UpdateZoomControls();
-
-    // If our zoom level changed, we need to tell the menu to update its state,
-    // since the menu could still be open.
-    wrench_menu_->UpdateMenu();
   } else {
     NOTREACHED();
   }
 }
 
 // BrowserToolbarGtk, public ---------------------------------------------------
 
 void BrowserToolbarGtk::UpdateWebContents(WebContents* contents,
                                           bool should_restore_state) {
   location_bar_->Update(should_restore_state ? contents : NULL);
@@ skipping 256 matching lines @@
                       allocation.x + x_offset,
                       allocation.y + y_offset);
 
   return FALSE;
 }
 
 void BrowserToolbarGtk::UpdateShowHomeButton() {
   bool visible = show_home_button_.GetValue() && !ShouldOnlyShowLocation();
   gtk_widget_set_visible(home_->widget(), visible);
 }