Add PlatformWindow/Event related code for Ozone X11.

ui/ozone/platform/x11/ozone_platform_x11.h

Index: ui/ozone/platform/x11/ozone_platform_x11.h
diff --git a/ui/ozone/platform/wayland/ozone_platform_wayland.h b/ui/ozone/platform/x11/ozone_platform_x11.h
similarity index 56%
copy from ui/ozone/platform/wayland/ozone_platform_wayland.h
copy to ui/ozone/platform/x11/ozone_platform_x11.h
index 2eb802cd4665307ef8fc8f3561e1d8b62026369c..b1f28a4fc7e971be44eb694bdf788d71e87de74a 100644
--- a/ui/ozone/platform/wayland/ozone_platform_wayland.h
+++ b/ui/ozone/platform/x11/ozone_platform_x11.h
@@ -2,16 +2,16 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef UI_OZONE_PLATFORM_DRM_OZONE_PLATFORM_WAYLAND_H_
-#define UI_OZONE_PLATFORM_DRM_OZONE_PLATFORM_WAYLAND_H_
+#ifndef UI_OZONE_PLATFORM_X11_OZONE_PLATFORM_X11_H_
+#define UI_OZONE_PLATFORM_X11_OZONE_PLATFORM_X11_H_
 
 namespace ui {
 
 class OzonePlatform;
 
 // Constructor hook for use in ozone_platform_list.cc
-OzonePlatform* CreateOzonePlatformWayland();
+OzonePlatform* CreateOzonePlatformX11();
 
 }  // namespace ui
 
-#endif  // UI_OZONE_PLATFORM_DRM_OZONE_PLATFORM_WAYLAND_H_
+#endif  // UI_OZONE_PLATFORM_X11_OZONE_PLATFORM_X11_H_