Add PlatformWindow/Event related code for Ozone X11.

ui/events/x/events_x_utils.cc

Index: ui/events/x/events_x_utils.cc
diff --git a/ui/events/x/events_x_utils.cc b/ui/events/x/events_x_utils.cc
index fb762f5294f1d8a2081e907cf04ad91e6c323161..a5247f2cd42d58b78be8e980484c8601e8dc1ad1 100644
--- a/ui/events/x/events_x_utils.cc
+++ b/ui/events/x/events_x_utils.cc
@@ -26,7 +26,6 @@
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/x/x11_atom_cache.h"
-#include "ui/gfx/x/x11_types.h"
 
 namespace {
 
@@ -306,6 +305,13 @@ bool GetGestureTimes(const XEvent& xev, double* start_time, double* end_time) {
 
 namespace ui {
 
+XID XWindowFromXEvent(const XEvent& xev) {
+  XID target = xev.xany.window;
+  if (xev.type == GenericEvent)
+    target = static_cast<XIDeviceEvent*>(xev.xcookie.data)->event;
+  return target;
+}
+
 EventType EventTypeFromXEvent(const XEvent& xev) {
   // Allow the DeviceDataManager to block the event. If blocked return
   // ET_UNKNOWN as the type so this event will not be further processed.