Refactor RenderWidgetHost::set_paint_observer()

chrome/browser/notifications/balloon_host.cc

 // Copyright (c) 2010 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/notifications/balloon_host.h"
 
 #include "chrome/browser/browser_list.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/notifications/balloon.h"
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/site_instance.h"
 #include "chrome/browser/renderer_preferences_util.h"
 #include "chrome/common/bindings_policy.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/notification_type.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/renderer_preferences.h"
 #include "chrome/common/url_constants.h"
 #include "webkit/glue/webpreferences.h"
 
-namespace {
-class BalloonPaintObserver : public RenderWidgetHost::PaintObserver {
- public:
-  explicit BalloonPaintObserver(BalloonHost* balloon_host)
-      : balloon_host_(balloon_host) {
-  }
-
-  virtual void RenderWidgetHostWillPaint(RenderWidgetHost* rhw) {}
-  virtual void RenderWidgetHostDidPaint(RenderWidgetHost* rwh);
-
- private:
-  BalloonHost* balloon_host_;
-
-  DISALLOW_COPY_AND_ASSIGN(BalloonPaintObserver);
-};
-
-void BalloonPaintObserver::RenderWidgetHostDidPaint(RenderWidgetHost* rwh) {
-  balloon_host_->RenderWidgetHostDidPaint();
-  // WARNING: we may have been deleted (if the balloon host cleared the paint
-  // observer).
-}
-
-}  // namespace
-
 BalloonHost::BalloonHost(Balloon* balloon)
     : render_view_host_(NULL),
       balloon_(balloon),
       initialized_(false),
       should_notify_on_disconnect_(false),
       enable_dom_ui_(false) {
   DCHECK(balloon_);
 
   // If the notification is for an extension URL, make sure to use the extension
   // process to render it, so that it can communicate with other views in the
@@ skipping 172 matching lines @@
   }
 
   // Do platform-specific initialization.
   render_view_host_ = rvh;
   InitRenderWidgetHostView();
   DCHECK(render_widget_host_view());
 
   rvh->set_view(render_widget_host_view());
   rvh->CreateRenderView(string16());
 #if defined(OS_MACOSX)
-  rvh->set_paint_observer(new BalloonPaintObserver(this));
+  registrar_.Add(this, NotificationType::RENDER_WIDGET_HOST_DID_PAINT,
+      Source<RenderWidgetHost>(render_view_host));
 #endif
   rvh->NavigateToURL(balloon_->notification().content_url());
 
   initialized_ = true;
 }
 
 void BalloonHost::EnableDOMUI() {
   DCHECK(render_view_host_ == NULL) <<
       "EnableDOMUI has to be called before a renderer is created.";
   enable_dom_ui_ = true;
 }
 
 void BalloonHost::UpdateInspectorSetting(const std::string& key,
                                          const std::string& value) {
   RenderViewHostDelegateHelper::UpdateInspectorSetting(
       GetProfile(), key, value);
 }
 
 void BalloonHost::ClearInspectorSettings() {
   RenderViewHostDelegateHelper::ClearInspectorSettings(GetProfile());
 }
 
-void BalloonHost::RenderWidgetHostDidPaint() {
-  render_view_host_->set_paint_observer(NULL);
-  render_view_host_->EnablePreferredSizeChangedMode(
-      kPreferredSizeWidth | kPreferredSizeHeightThisIsSlow);
+void BalloonHost::Observe(NotificationType type,
+    const NotificationSource& source,
+    const NotificationDetails& details) {
+  if (type == NotificationType::RENDER_WIDGET_HOST_DID_PAINT) {
+    registrar_.RemoveAll();
+    render_view_host_->EnablePreferredSizeChangedMode(
+        kPreferredSizeWidth | kPreferredSizeHeightThisIsSlow);
+  }
 }
 
 BalloonHost::~BalloonHost() {
   DCHECK(!render_view_host_);
 }
 
 void BalloonHost::NotifyDisconnect() {
   if (!should_notify_on_disconnect_)
     return;
 
   should_notify_on_disconnect_ = false;
   NotificationService::current()->Notify(
       NotificationType::NOTIFY_BALLOON_DISCONNECTED,
       Source<BalloonHost>(this), NotificationService::NoDetails());
 }