aura: A few changes to have aura_demo compile and run on linux.

aura/event.h

 // Copyright (c) 2011 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 AURA_EVENT_H_
 #define AURA_EVENT_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/time.h"
 #include "ui/base/events.h"
 #include "ui/base/keycodes/keyboard_codes.h"
 #include "ui/gfx/point.h"
 
+#if defined(USE_X11)
+typedef union _XEvent XEvent;
+#endif
+
 namespace aura {
 
 #if defined(OS_WIN)
 typedef MSG NativeEvent;
 #elif defined(USE_X11)
-typedef union _XEvent XEvent;
 typedef XEvent* NativeEvent;
 #endif
 
 class Window;
 
 class Event {
  public:
   const NativeEvent& native_event() const { return native_event_; }
   ui::EventType type() const { return type_; }
   const base::Time& time_stamp() const { return time_stamp_; }
@@ skipping 67 matching lines @@
 
   ui::KeyboardCode key_code() const { return key_code_; }
 
  private:
   ui::KeyboardCode key_code_;
 };
 
 }  // namespace aura
 
 #endif  // AURA_EVENT_H_