content: convert zoom notifications to observer usage

chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.mm

 // Copyright (c) 2011 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.
 
 #import "chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.h"
 
 #include "base/basictypes.h"
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
 #include "base/string16.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #import "chrome/browser/app_controller_mac.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #import "chrome/browser/ui/cocoa/accelerators_cocoa.h"
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_menu_bridge.h"
 #import "chrome/browser/ui/cocoa/encoding_menu_controller_delegate_mac.h"
 #import "chrome/browser/ui/cocoa/toolbar/toolbar_controller.h"
 #import "chrome/browser/ui/cocoa/wrench_menu/menu_tracked_root_view.h"
 #import "chrome/browser/ui/cocoa/wrench_menu/recent_tabs_menu_model_delegate.h"
 #include "chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.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_service.h"
-#include "content/public/browser/notification_source.h"
-#include "content/public/browser/notification_types.h"
 #include "content/public/browser/user_metrics.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/models/menu_model.h"
 
 using content::HostZoomMap;
 using content::UserMetricsAction;
 
 @interface WrenchMenuController (Private)
@@ skipping 17 matching lines @@
     AcceleratorsCocoa* keymap = AcceleratorsCocoa::GetInstance();
     const ui::Accelerator* accelerator =
         keymap->GetAcceleratorForCommand(command_id);
     if (!accelerator)
       return false;
     *out_accelerator = *accelerator;
     return true;
   }
 };
 
-class ZoomLevelObserver : public content::NotificationObserver {
+class ZoomLevelObserver {
  public:
-  explicit ZoomLevelObserver(WrenchMenuController* controller)
-      : controller_(controller) {
-    registrar_.Add(
-        this, content::NOTIFICATION_ZOOM_LEVEL_CHANGED,
-        content::NotificationService::AllBrowserContextsAndSources());
+  ZoomLevelObserver(WrenchMenuController* controller,
+                    content::HostZoomMap* map)
+      : controller_(controller),
+        map_(map) {
+    map_->AddZoomLevelChangedCallback(base::Bind(
+        &ZoomLevelObserver::OnZoomLevelChanged, base::Unretained(this)));
   }
 
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) {
-    DCHECK_EQ(type, content::NOTIFICATION_ZOOM_LEVEL_CHANGED);
+  ~ZoomLevelObserver() {
+    map_->RemoveZoomLevelChangedCallback(base::Bind(
+        &ZoomLevelObserver::OnZoomLevelChanged, base::Unretained(this)));
+  }
+
+  void OnZoomLevelChanged(const std::string& host) {
     WrenchMenuModel* wrenchMenuModel = [controller_ wrenchMenuModel];
-    if (HostZoomMap::GetForBrowserContext(
-            wrenchMenuModel->browser()->profile()) !=
-        content::Source<HostZoomMap>(source).ptr()) {
-      return;
-    }
-
     wrenchMenuModel->UpdateZoomControls();
     const string16 level =
         wrenchMenuModel->GetLabelForCommandId(IDC_ZOOM_PERCENT_DISPLAY);
     [[controller_ zoomDisplay] setTitle:SysUTF16ToNSString(level)];
   }
 
  private:
-  content::NotificationRegistrar registrar_;
   WrenchMenuController* controller_;  // Weak; owns this.
+  content::HostZoomMap* map_;  // Weak.
+
+  DISALLOW_COPY_AND_ASSIGN(ZoomLevelObserver);
 };
 
 }  // namespace WrenchMenuControllerInternal
 
 @implementation WrenchMenuController
 
 - (id)initWithBrowser:(Browser*)browser {
   if ((self = [super init])) {
     browser_ = browser;
-    observer_.reset(new WrenchMenuControllerInternal::ZoomLevelObserver(self));
+    observer_.reset(new WrenchMenuControllerInternal::ZoomLevelObserver(
+        self, content::HostZoomMap::GetForBrowserContext(browser->profile())));
     acceleratorDelegate_.reset(
         new WrenchMenuControllerInternal::AcceleratorDelegate());
     [self createModel];
   }
   return self;
 }
 
 - (void)addItemToMenu:(NSMenu*)menu
               atIndex:(NSInteger)index
             fromModel:(ui::MenuModel*)model {
@@ skipping 243 matching lines @@
     controller_ = controller;
   }
   return self;
 }
 
 - (IBAction)dispatchWrenchMenuCommand:(id)sender {
   [controller_ dispatchWrenchMenuCommand:sender];
 }
 
 @end  // @implementation WrenchMenuButtonViewController