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..cd8ddd3125dfd852010623747c9fe9b36a72d0dd
--- /dev/null
+++ b/ui/events/platform/x11/x11_event_source_libevent.h
@@ -0,0 +1,81 @@
+// 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_pump_libevent.h"
+#include "ui/events/events_export.h"
+#include "ui/events/platform/platform_event_source.h"
+#include "ui/events/platform/x11/x11_event_source.h"
+
+namespace ui {
+
+// Interface for classes that want to receive XEvent directly. Only used with
+// Ozone X11 currently and only events that can't be translated into ui::Events
+// are sent via this path.
+class EVENTS_EXPORT XEventDispatcher {
+ public:
+  // Sends XEvent to XEventDispatcher for handling. Returns true if the XEvent
+  // was dispatched, otherwise false. After the first XEventDispatcher returns
+  // true XEvent dispatching stops.
+  virtual bool DispatchXEvent(XEvent* xevent) = 0;
+
+ protected:
+  virtual ~XEventDispatcher() {}
+};
+
+// A PlatformEventSource implementation for Ozone X11. Converts XEvents to
+// ui::Events before dispatching.  For X11 specific events a separate list of
+// XEventDispatchers is maintained. Uses Libevent to be notified for incoming
+// XEvents.
+class EVENTS_EXPORT X11EventSourceLibevent
+    : public X11EventSourceDelegate,
+      public PlatformEventSource,
+      public base::MessagePumpLibevent::Watcher {
+ public:
+  explicit X11EventSourceLibevent(XDisplay* display);
+  ~X11EventSourceLibevent() override;
+
+  static X11EventSourceLibevent* GetInstance();

[sadrul, 2016/02/08 17:28:32]

Looks like we need this only from X11WindowOzone. Instead of X11WindowOzone
looking up this singleton instance, can we have OzonePlatformX11 explicitly send
the X11EventSourceLibevent to the X11WindowOzone instances instead?

[kylechar, 2016/02/08 19:08:09]

Done.

+
+  // X11EventSourceDelegate:
+  void ProcessXEvent(XEvent* xevent) override;
+
+  // Adds a XEvent dispatcher to the XEvent dispatcher list.
+  void AddXEventDispatcher(XEventDispatcher* dispatcher);
+
+  // Removes a XEvent dispatcher fERrom the XEvent dispatcher list.
+  void RemoveXEventDispatcher(XEventDispatcher* dispatcher);

[sadrul, 2016/02/08 17:28:32]

These should go before the override. (make sure to update the order in .cc to
match the order in .h too)

[kylechar, 2016/02/08 19:08:10]

Done.

+
+ private:
+  // PlatformEventSource:
+  void StopCurrentEventStream() override;
+  void OnDispatcherListChanged() override;
+
+  // Registers event watcher with Libevent.
+  void AddEventWatcher();
+
+  // Sends XEvent to registered XEventDispatchers.
+  void DispatchXEventToXEventDispatchers(XEvent* xevent);

[sadrul, 2016/02/08 17:28:33]

ditto

[kylechar, 2016/02/08 19:08:10]

Done.

+
+  // base::MessagePumpLibevent::Watcher:
+  void OnFileCanReadWithoutBlocking(int fd) override;
+  void OnFileCanWriteWithoutBlocking(int fd) override;
+
+  scoped_ptr<X11EventSource> event_source_;

[sadrul, 2016/02/08 17:28:33]

This doesn't need to be a scoped_ptr<>?

[kylechar, 2016/02/08 19:08:10]

Done.

+
+  // Keep track of all XEventDispatcher to send XEvents directly to.
+  base::ObserverList<XEventDispatcher> dispatchers_xevent_;
+
+  base::MessagePumpLibevent::FileDescriptorWatcher watcher_controller_;
+  bool initialized_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(X11EventSourceLibevent);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_LIBEVENT_H_