Add PlatformWindow/Event related code for Ozone X11.

ui/events/platform/x11/x11_event_source_libevent.h

Index: ui/events/platform/x11/x11_event_source_libevent.h
diff --git a/ui/events/platform/x11/x11_event_source_libevent.h b/ui/events/platform/x11/x11_event_source_libevent.h
new file mode 100644
index 0000000000000000000000000000000000000000..15a9984fa15f36e8c6f4948cbc5498a93a7e522f
--- /dev/null
+++ b/ui/events/platform/x11/x11_event_source_libevent.h
@@ -0,0 +1,42 @@
+// Copyright 2016 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_PLATFORM_X11_X11_EVENT_SOURCE_LIBEVENT_H_
+#define UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_LIBEVENT_H_
+
+#include "base/macros.h"
+#include "base/message_loop/message_loop.h"
+#include "base/message_loop/message_pump_libevent.h"
+#include "ui/events/events_export.h"
+#include "ui/events/platform/x11/x11_event_source.h"
+
+namespace ui {
+
+class EVENTS_EXPORT X11EventSourceLibevent
+    : public X11EventSource,
+      public base::MessagePumpLibevent::Watcher {
+ public:
+  explicit X11EventSourceLibevent(XDisplay* display);
+
+  ~X11EventSourceLibevent() override;
+
+ private:
+  void AddEventWatcher();
+
+  // PlatformEventSource:
+  void OnDispatcherListChanged() override;
+
+  // base::MessagePumpLibevent::Watcher:
+  void OnFileCanReadWithoutBlocking(int fd) override;
+  void OnFileCanWriteWithoutBlocking(int fd) override;
+
+  base::MessagePumpLibevent::FileDescriptorWatcher watcher_controller_;
+  bool initialized_;
+
+  DISALLOW_COPY_AND_ASSIGN(X11EventSourceLibevent);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_LIBEVENT_H_