IPC::ParamTraits for ui::PointerEvent.

ui/events/event.h

Index: ui/events/event.h
diff --git a/ui/events/event.h b/ui/events/event.h
index ca383d70a33054b0b2e0758c4392ea84ebda61ee..def42660efecdab55a7108288ab1fcb7e349f839 100644
--- a/ui/events/event.h
+++ b/ui/events/event.h
@@ -752,6 +752,13 @@ class EVENTS_EXPORT PointerEvent : public LocatedEvent {
   int32_t pointer_id() const { return pointer_id_; }
   const PointerDetails& pointer_details() const { return details_; }
 
+ protected:
+  // For (de)serialization.
+  PointerEvent(EventType type, base::TimeDelta time_stamp, int flags)
+      : LocatedEvent(type, time_stamp, flags) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::PointerEvent>;
+
  private:
   int32_t pointer_id_;
   PointerDetails details_;