x11: Make the event-source work with both glib and libevent message-pumps.

ui/events/platform/x11/x11_event_source_libevent.cc

+// 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.
+
+#include "ui/events/platform/x11/x11_event_source.h"
+
+#include <X11/Xlib.h>
+
+#include "base/message_loop/message_loop.h"
+#include "base/message_loop/message_pump_libevent.h"
+
+namespace ui {
+
+namespace {
+
+class X11EventSourceLibevent : public X11EventSource,
+                               public base::MessagePumpLibevent::Watcher {
+ public:
+  explicit X11EventSourceLibevent(XDisplay* display)
+      : X11EventSource(display) {
+    int fd = ConnectionNumber(display);
+    base::MessageLoopForUI::current()->WatchFileDescriptor(fd, true,
+        base::MessagePumpLibevent::WATCH_READ, &watcher_controller_, this);
+  }
+
+  virtual ~X11EventSourceLibevent() {
+  }
+
+ private:
+  // base::MessagePumpLibevent::Watcher:
+  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE {
+    DispatchXEvents();
+  }
+
+  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE {
+    NOTREACHED();
+  }
+
+  base::MessagePumpLibevent::FileDescriptorWatcher watcher_controller_;
+
+  DISALLOW_COPY_AND_ASSIGN(X11EventSourceLibevent);
+};
+
+}  // namespace
+
+scoped_ptr<PlatformEventSource> PlatformEventSource::CreateDefault() {
+  return scoped_ptr<PlatformEventSource>(
+      new X11EventSourceLibevent(gfx::GetXDisplay()));
+}
+
+}  // namespace ui