--downloads-new-ui completely disables the download shelf.

chrome/common/chrome_switches.cc

 // Copyright (c) 2011 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/common/chrome_switches.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 
 namespace switches {
@@ skipping 214 matching lines @@
 const char kDisableCustomJumpList[]         = "disable-custom-jumplist";
 
 // Disables checking whether custom protocol handlers are registered with the
 // OS and removing those that are not. This is used during automated testing.
 const char kDisableCustomProtocolOSCheck[]  =
     "disable-custom-protocol-os-check";
 
 // Disables retrieval of PAC URLs from DHCP as per the WPAD standard.
 const char kDisableDhcpWpad[]               = "disable-dhcp-wpad";
 
+// Disables the download shelf.
+const char kDisableDownloadShelf[]          = "disable-download-shelf";
+
 // Disable extensions.
 const char kDisableExtensions[]             = "disable-extensions";
 
 // Disable checking for user opt-in for extensions that want to inject script
 // into file URLs (ie, always allow it). This is used during automated testing.
 const char kDisableExtensionsFileAccessCheck[] =
     "disable-extensions-file-access-check";
 
 // Disables the sandbox for the built-in flash player.
 const char kDisableFlashSandbox[]           = "disable-flash-sandbox";
@@ skipping 984 matching lines @@
 
 // -----------------------------------------------------------------------------
 // DO NOT ADD YOUR CRAP TO THE BOTTOM OF THIS FILE.
 //
 // You were going to just dump your switches here, weren't you? Instead,
 // please put them in alphabetical order above, or in order inside the
 // appropriate ifdef at the bottom. The order should match the header.
 // -----------------------------------------------------------------------------
 
 }  // namespace switches