[Download Notification] Disable download notification by default on ChromeOS

chrome/browser/download/notification/download_notification_manager.cc

Index: chrome/browser/download/notification/download_notification_manager.cc
diff --git a/chrome/browser/download/notification/download_notification_manager.cc b/chrome/browser/download/notification/download_notification_manager.cc
index c948568c53d5e3a1b6922d55bf32ead7ea01c87f..04a30a3d4d9b530c165862bbc19b14bf925713d0 100644
--- a/chrome/browser/download/notification/download_notification_manager.cc
+++ b/chrome/browser/download/notification/download_notification_manager.cc
@@ -25,11 +25,8 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 bool DownloadNotificationManager::IsEnabled() {
-#if defined(OS_CHROMEOS)
-  bool enable_download_notification = true;
-#else
+  // Disabled by default.
   bool enable_download_notification = false;
-#endif
 
   std::string arg = base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
       switches::kEnableDownloadNotification);