Remove kDisableDownloadNotification and stop compiling shelf code on

chrome/browser/extensions/api/downloads/downloads_api.cc

Index: chrome/browser/extensions/api/downloads/downloads_api.cc
diff --git a/chrome/browser/extensions/api/downloads/downloads_api.cc b/chrome/browser/extensions/api/downloads/downloads_api.cc
index 0a297d2116bd4a67bd2bed82ea1b9fbfa9a1556f..fe712afecadda8bae996f22bf89c237a1c40ca89 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api.cc
@@ -1429,13 +1429,14 @@ bool DownloadsSetShelfEnabledFunction::RunSync() {
         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() &&
@@ -1443,6 +1444,7 @@ bool DownloadsSetShelfEnabledFunction::RunSync() {
         browser->window()->GetDownloadShelf()->Close(DownloadShelf::AUTOMATIC);
     }
   }
+#endif
 
   if (params->enabled &&
       ((manager && !service->IsShelfEnabled()) ||