Convert zoom callbacks to use CallbackRegistry

chrome/browser/ui/zoom/zoom_controller.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/zoom/zoom_controller.h"
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/page_zoom.h"
 #include "grit/theme_resources.h"
 #include "net/base/net_util.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ZoomController);
 
 ZoomController::ZoomController(content::WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
       zoom_percent_(100),
       observer_(NULL),
-      browser_context_(web_contents->GetBrowserContext()),
-      zoom_callback_(base::Bind(&ZoomController::OnZoomLevelChanged,
-                                base::Unretained(this))) {
+      browser_context_(web_contents->GetBrowserContext()) {
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
   default_zoom_level_.Init(prefs::kDefaultZoomLevel, profile->GetPrefs(),
                            base::Bind(&ZoomController::UpdateState,
                                       base::Unretained(this),
                                       std::string()));
 
-  content::HostZoomMap::GetForBrowserContext(
+  zoom_subscription_ = content::HostZoomMap::GetForBrowserContext(
       browser_context_)->AddZoomLevelChangedCallback(
-          zoom_callback_);
+          base::Bind(&ZoomController::OnZoomLevelChanged,
+                     base::Unretained(this)));
 
   UpdateState(std::string());
 }
 
-ZoomController::~ZoomController() {
-  content::HostZoomMap::GetForBrowserContext(
-      browser_context_)->RemoveZoomLevelChangedCallback(
-          zoom_callback_);
-}
+ZoomController::~ZoomController() {}
 
 bool ZoomController::IsAtDefaultZoom() const {
   return content::ZoomValuesEqual(web_contents()->GetZoomLevel(),
                                   default_zoom_level_.GetValue());
 }
 
 int ZoomController::GetResourceForZoomLevel() const {
   if (IsAtDefaultZoom())
     return IDR_ZOOM_NORMAL;
   double zoom = web_contents()->GetZoomLevel();
@@ skipping 25 matching lines @@
       return;
     }
   }
 
   bool dummy;
   zoom_percent_ = web_contents()->GetZoomPercent(&dummy, &dummy);
 
   if (observer_)
     observer_->OnZoomChanged(web_contents(), !host.empty());
 }