Remove X11/Xlib.h include from selection_requestor.h

ui/gfx/x/x11_types.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_GFX_X_X11_UTIL_H_
 #define UI_GFX_X_X11_UTIL_H_
 
 #include "base/basictypes.h"
 #include "ui/gfx/gfx_export.h"
 
+typedef unsigned long XAtom;
 typedef unsigned long XID;
 typedef struct _XImage XImage;
 typedef struct _XGC *GC;
 typedef struct _XDisplay XDisplay;
 
 namespace gfx {
 
 // TODO(oshima|evan): This assume there is one display and doesn't work
 // undef multiple displays/monitor environment. Remove this and change the
 // chrome codebase to get the display from window.
@@ skipping 25 matching lines @@
                              const uint8* data,
                              int data_width, int data_height,
                              int src_x, int src_y,
                              int dst_x, int dst_y,
                              int copy_width, int copy_height);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_X_X11_UTIL_H_