Make the UI an observer of downloads.

chrome/browser/download/download_service.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/download/download_service.h"
 
 #include "base/callback.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/download/chrome_download_manager_delegate.h"
 #include "chrome/browser/download/download_history.h"
 #include "chrome/browser/download/download_service_factory.h"
 #include "chrome/browser/download/download_status_updater.h"
+#include "chrome/browser/download/download_ui_controller.h"
 #include "chrome/browser/extensions/api/downloads/downloads_api.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/net/chrome_net_log.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "content/public/browser/download_manager.h"
 
 using content::BrowserContext;
 using content::DownloadManager;
@@ skipping 31 matching lines @@
   if (!profile_->IsOffTheRecord()) {
     HistoryService* hs = HistoryServiceFactory::GetForProfile(
         profile_, Profile::EXPLICIT_ACCESS);
     if (hs)
       download_history_.reset(new DownloadHistory(
           manager,
           scoped_ptr<DownloadHistory::HistoryAdapter>(
             new DownloadHistory::HistoryAdapter(hs))));
   }
 
+  // Pass an empty delegate when constructing the DownloadUIController. The
+  // default delegate does all the notifications we need.
+  scoped_ptr<DownloadUIController::Delegate> empty_ui_delegate;
+  download_ui_.reset(new DownloadUIController(manager,
+                                              empty_ui_delegate.Pass()));
+
   // Include this download manager in the set monitored by the
   // global status updater.
   g_browser_process->download_status_updater()->AddManager(manager);
 
   return manager_delegate_.get();
 }
 
 DownloadHistory* DownloadService::GetDownloadHistory() {
   if (!download_manager_created_) {
     GetDownloadManagerDelegate();
@@ skipping 51 matching lines @@
     // code) when the DownloadManager is shutting down. So we shut it down
     // manually earlier. See http://crbug.com/131692
     BrowserContext::GetDownloadManager(profile_)->Shutdown();
   }
 #if !defined(OS_ANDROID)
   extension_event_router_.reset();
 #endif
   manager_delegate_ = NULL;
   download_history_.reset();
 }