Enable Device Discovery by default on Linux, ChromeOS and Windows.

chrome/browser/browser_about_handler.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/browser_about_handler.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 58 matching lines @@
   } else if (host == chrome::kChromeUIHelpHost) {
     host = chrome::kChromeUIUberHost;
     path = chrome::kChromeUIHelpHost + url->path();
   } else if (host == chrome::kChromeUIRestartHost) {
     // Call AttemptRestart after chrome::Navigate() completes to avoid access of
     // gtk objects after they are destoyed by BrowserWindowGtk::Close().
     base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(&chrome::AttemptRestart));
   } else if (host == chrome::kChromeUIDevicesHost) {
 #if defined(ENABLE_MDNS)
-    if (CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kEnableDeviceDiscovery)) {
+    if (!CommandLine::ForCurrentProcess()->HasSwitch(
+            switches::kDisableDeviceDiscovery)) {
       host = chrome::kChromeUIUberHost;
       path = chrome::kChromeUIDevicesHost + url->path();
     }
 #endif
   }
 
   GURL::Replacements replacements;
   replacements.SetHostStr(host);
   if (!path.empty())
     replacements.SetPathStr(path);
@@ skipping 12 matching lines @@
     // Run the dialog. This will re-use the existing one if it's already up.
     chrome::ShowAboutIPCDialog();
     return true;
   }
 #endif
 
 #endif  // OFFICIAL_BUILD
 
   return false;
 }