Remove kDisableDownloadNotification and stop compiling shelf code on

chrome/browser/extensions/api/downloads/downloads_api.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/extensions/api/downloads/downloads_api.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <set>
 #include <string>
@@ skipping 1411 matching lines @@
     service->GetExtensionEventRouter()->SetShelfEnabled(extension(),
                                                         params->enabled);
   }
   if (incognito_manager) {
     incognito_service = DownloadServiceFactory::GetForBrowserContext(
         incognito_manager->GetBrowserContext());
     incognito_service->GetExtensionEventRouter()->SetShelfEnabled(
         extension(), params->enabled);
   }
 
+#if !defined(OS_CHROMEOS)
   BrowserList* browsers = BrowserList::GetInstance();
   if (browsers) {
     for (BrowserList::const_iterator iter = browsers->begin();
         iter != browsers->end(); ++iter) {
       const Browser* browser = *iter;
       DownloadService* current_service =
-        DownloadServiceFactory::GetForBrowserContext(browser->profile());
+          DownloadServiceFactory::GetForBrowserContext(browser->profile());
       if (((current_service == service) ||
            (current_service == incognito_service)) &&
           browser->window()->IsDownloadShelfVisible() &&
           !current_service->IsShelfEnabled())
         browser->window()->GetDownloadShelf()->Close(DownloadShelf::AUTOMATIC);
     }
   }
+#endif
 
   if (params->enabled &&
       ((manager && !service->IsShelfEnabled()) ||
        (incognito_manager && !incognito_service->IsShelfEnabled()))) {
     error_ = download_extension_errors::kShelfDisabled;
     return false;
   }
 
   return true;
 }
@@ skipping 447 matching lines @@
     return;
   base::Time now(base::Time::Now());
   int delta = now.ToTimeT() - last_checked_removal_.ToTimeT();
   if (delta <= kFileExistenceRateLimitSeconds)
     return;
   last_checked_removal_ = now;
   manager->CheckForHistoryFilesRemoval();
 }
 
 }  // namespace extensions