Remove NOTIFICATION_RENDER_VIEW_HOST_CHANGED.

chrome/browser/ui/panels/panel.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/panels/panel.h"
 
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
@@ skipping 419 matching lines @@
     default:
       LOG(WARNING) << "Received unimplemented command: " << id;
       break;
   }
 }
 
 void Panel::Observe(int type,
                     const content::NotificationSource& source,
                     const content::NotificationDetails& details) {
   switch (type) {
-    case content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED:
-      ConfigureAutoResize(content::Source<content::WebContents>(source).ptr());
-      break;
     case chrome::NOTIFICATION_APP_TERMINATING:
       Close();
       break;
     default:
       NOTREACHED() << "Received unexpected notification " << type;
   }
 }
 
+void Panel::RenderViewHostChanged(content::RenderViewHost* old_host,
+                                  content::RenderViewHost* new_host) {
+  ConfigureAutoResize(web_contents());
+}
+
 void Panel::OnExtensionUnloaded(
     content::BrowserContext* browser_context,
     const extensions::Extension* extension,
     extensions::UnloadedExtensionInfo::Reason reason) {
   if (extension->id() == extension_id())
     Close();
 }
 void Panel::OnTitlebarClicked(panel::ClickModifier modifier) {
   if (collection_)
     collection_->OnPanelTitlebarClicked(this, modifier);
@@ skipping 125 matching lines @@
   if (auto_resizable_ == resizable)
     return;
 
   auto_resizable_ = resizable;
   content::WebContents* web_contents = GetWebContents();
   if (auto_resizable_) {
     if (web_contents)
       EnableWebContentsAutoResize(web_contents);
   } else {
     if (web_contents) {
-      registrar_.Remove(this, content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
-                        content::Source<content::WebContents>(web_contents));
+      content::WebContentsObserver::Observe(nullptr);
 
       // NULL might be returned if the tab has not been added.
       RenderViewHost* render_view_host = web_contents->GetRenderViewHost();
       if (render_view_host)
         render_view_host->DisableAutoResize(full_size_);
     }
   }
 }
 
 void Panel::EnableWebContentsAutoResize(content::WebContents* web_contents) {
   DCHECK(web_contents);
   ConfigureAutoResize(web_contents);
 
   // We also need to know when the render view host changes in order
   // to turn on auto-resize notifications in the new render view host.
-  if (!registrar_.IsRegistered(
-          this, content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
-          content::Source<content::WebContents>(web_contents))) {
-    registrar_.Add(
-        this,
-        content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
-        content::Source<content::WebContents>(web_contents));
-  }
+  content::WebContentsObserver::Observe(web_contents);
 }
 
 void Panel::OnContentsAutoResized(const gfx::Size& new_content_size) {
   DCHECK(auto_resizable_);
   if (!collection_)
     return;
 
   gfx::Size new_window_size =
       native_panel_->WindowSizeFromContentSize(new_content_size);
 
@@ skipping 265 matching lines @@
 // static
 void Panel::FormatTitleForDisplay(base::string16* title) {
   size_t current_index = 0;
   size_t match_index;
   while ((match_index = title->find(L'\n', current_index)) !=
          base::string16::npos) {
     title->replace(match_index, 1, base::string16());
     current_index = match_index;
   }
 }