Remove kDisableDownloadNotification and stop compiling shelf code on

chrome/browser/ui/chrome_pages.cc

Index: chrome/browser/ui/chrome_pages.cc
diff --git a/chrome/browser/ui/chrome_pages.cc b/chrome/browser/ui/chrome_pages.cc
index 4434c4df8e06f6800065bab02f3ac370925d91ba..7da0e4453d541f6fd8311f43d61d886d63067529 100644
--- a/chrome/browser/ui/chrome_pages.cc
+++ b/chrome/browser/ui/chrome_pages.cc
@@ -160,9 +160,10 @@ void ShowHistory(Browser* browser) {
 
 void ShowDownloads(Browser* browser) {
   content::RecordAction(UserMetricsAction("ShowDownloads"));
+#if !defined(OS_CHROMEOS)
   if (browser->window() && browser->window()->IsDownloadShelfVisible())
     browser->window()->GetDownloadShelf()->Close(DownloadShelf::USER_ACTION);
-
+#endif
   ShowSingletonTabOverwritingNTP(
       browser,
       GetSingletonTabNavigateParams(browser, GURL(kChromeUIDownloadsURL)));