evdev: Fix infinite loop when devices are unplugged

ui/events/ozone/event_converter_ozone.h

 // Copyright (c) 2013 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 UI_EVENTS_OZONE_EVENT_CONVERTER_OZONE_H_
 #define UI_EVENTS_OZONE_EVENT_CONVERTER_OZONE_H_
 
 #include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_pump_libevent.h"
 #include "ui/events/events_export.h"
 
 namespace ui {
 class Event;
 
-// In ozone, Chrome reads events from file descriptors created from Linux device
-// drivers. The |MessagePumpLibevent::Watcher| parent class provides the
-// functionality to watch a file descriptor for the arrival of new data and
-// notify its subclasses. Device-specific event converters turn bytes read from
-// the file descriptor into |ui::Event| instances. This class provides the
-// functionality needed in common across all converters: dispatching the
-// |ui::Event| to aura.
-class EVENTS_EXPORT EventConverterOzone
-    : public base::MessagePumpLibevent::Watcher {
+// Ozone implementations can generate input events in whatever way is
+// appropriate for the platform.
+// This class provides the functionality needed in common across all
+// converters: dispatching the |ui::Event| to aura.
+class EVENTS_EXPORT EventConverterOzone {
  public:
   EventConverterOzone();
   virtual ~EventConverterOzone();
 
+  // Start processing events.

[rjkroege, 2014/01/27 19:03:16]

Is it re-startable? I.e.: would one ever call Stop() and then later call
Start()?

Should Start and Stop be implicit on the constructor and destructor?

+  virtual void Start() = 0;
+
+  // Stop processing events.
+  virtual void Stop() = 0;
+
  protected:
   // Subclasses should use this method to post a task that will dispatch
   // |event| from the UI message loop. This method takes ownership of
   // |event|. |event| will be deleted at the end of the posted task.
   virtual void DispatchEvent(scoped_ptr<ui::Event> event);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(EventConverterOzone);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_OZONE_EVENT_CONVERTER_OZONE_H_