Move DeviceMonitorLinux to //device/core.

device/core/device_monitor_linux.h

 // Copyright 2014 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.
 
 #ifndef DEVICE_HID_DEVICE_MONITOR_LINUX_H_
 #define DEVICE_HID_DEVICE_MONITOR_LINUX_H_
 
 #include <memory>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_pump_libevent.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
+#include "device/core/device_core_export.h"
 #include "device/udev_linux/scoped_udev.h"
 
 struct udev_device;
 
 namespace device {
 
 // This class listends for notifications from libudev about
 // connected/disconnected devices. This class is *NOT* thread-safe and
 // all methods must be accessed from the FILE thread.
-class DeviceMonitorLinux : public base::MessageLoop::DestructionObserver,
-                           public base::MessagePumpLibevent::Watcher {
+class DEVICE_CORE_EXPORT DeviceMonitorLinux
+    : public base::MessageLoop::DestructionObserver,
+      public base::MessagePumpLibevent::Watcher {
  public:
   typedef base::Callback<void(udev_device* device)> EnumerateCallback;
 
   class Observer {
    public:
     virtual ~Observer() {}
     virtual void OnDeviceAdded(udev_device* device) = 0;
     virtual void OnDeviceRemoved(udev_device* device) = 0;
+    virtual void WillDestroyMonitorMessageLoop() = 0;
   };
 
   DeviceMonitorLinux();
 
   static DeviceMonitorLinux* GetInstance();
-  static bool HasInstance();
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   ScopedUdevDevicePtr GetDeviceFromPath(const std::string& path);
   void Enumerate(const EnumerateCallback& callback);
 
   // Implements base::MessageLoop::DestructionObserver
   void WillDestroyCurrentMessageLoop() override;
 
@@ skipping 14 matching lines @@
   base::ObserverList<Observer, true> observers_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceMonitorLinux);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_HID_DEVICE_MONITOR_LINUX_H_