Make it possible to disable udev in linux

content/browser/device_monitor_linux.h

 // 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.
 
 // This class is used to detect device change and notify base::SystemMonitor
 // on Linux.
 
 #ifndef CONTENT_BROWSER_DEVICE_MONITOR_LINUX_H_
 #define CONTENT_BROWSER_DEVICE_MONITOR_LINUX_H_
 
+#if !defined(USE_UDEV)

[rjkroege, 2013/11/15 23:16:31]

my very badly worded comment from before remains.

if you renamed this file device_monitor_udev.h and added a name pattern, then
this test here would be unnecessary: the build system would not compile the file
unless USE_UDEV was defined?

[Mostyn Bramley-Moore, 2013/11/15 23:49:43]

Done.

+#error USE_UDEV must be defined.
+#endif
+
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 
 extern "C" {
 struct udev_device;
 }
 
 namespace content {
 
@@ skipping 14 matching lines @@
   void OnDevicesChanged(udev_device* device);
 
   scoped_ptr<UdevLinux> udev_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceMonitorLinux);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVICE_MONITOR_LINUX_H_