Enable chrome://discards on Linux.

chrome/browser/ui/webui/chrome_web_ui_controller_factory.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/ui/webui/chrome_web_ui_controller_factory.h"
 
 #include <stddef.h>
 
 #include <vector>
 
@@ skipping 298 matching lines @@
 #if !defined(OS_ANDROID)
           || url.host() == chrome::kChromeUITermsHost
 #endif
 #if defined(OS_LINUX) || defined(OS_OPENBSD)
           || url.host() == chrome::kChromeUILinuxProxyConfigHost ||
           url.host() == chrome::kChromeUISandboxHost
 #endif
 #if defined(OS_CHROMEOS)
           || url.host() == chrome::kChromeUIOSCreditsHost
 #endif
-#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_CHROMEOS)
+#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
           || url.host() == chrome::kChromeUIDiscardsHost
 #endif
           );  // NOLINT
 }
 
 // Returns a function that can be used to create the right type of WebUI for a
 // tab, based on its URL. Returns NULL if the URL doesn't have WebUI associated
 // with it.
 WebUIFactoryFunction GetWebUIFactoryFunction(WebUI* web_ui,
                                              Profile* profile,
@@ skipping 518 matching lines @@
 #endif
 
   // Android doesn't use the plugins pages.
   if (page_url.host() == chrome::kChromeUIPluginsHost)
     return PluginsUI::GetFaviconResourceBytes(scale_factor);
 
 #endif
 
   return NULL;
 }