Yep, Hadi (moshayedi@) is working on it (wip CL https://codereview.chromium.org/1939133002/)

Hadi: what's the status of the CL?

It was blocked on  crbug.com/610729 . rockot@ suggested that we can typemap to unique_ptr<ui::Event> (instead of typemapping to ui::Event) to solve the problem described in  crbug.com/610729  (I had misunderstood it earlier, so I was waiting for further updates from their side). I'll update the CL accordingly and send it for review soon.

See https://bugs.chromium.org/p/chromium/issues/detail?id=615102 for my 2cents about event polymorphism.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ef4e847c615cc3fa778d84586578409d8d4f0895

commit ef4e847c615cc3fa778d84586578409d8d4f0895
Author: moshayedi <moshayedi@chromium.org>
Date: Wed Jun 01 20:46:15 2016

Constructors for ui::MouseEvent/ui::TouchEvent from ui::PointerEvent.

We don't support ui::PointerEvents in mus+ash client side right now, so we
need to convert ui::PointerEvent to ui::MouseEvent/ui::TouchEvent until we
have a better solution. This CL adds constructors we need so we can do this
conversion.

Previously this conversion happened when we deserialized mojom::Event to
ui::Event, but that didn't seem the correct place to do it, since we
serialized ui::PointerEvent (and not touch/mouse events) to mojom::Event, and
we should get the same kind of object when deserializing.

BUG= 615094 

Review-Url: https://codereview.chromium.org/2029713002
Cr-Commit-Position: refs/heads/master@{#397236}

[modify] https://crrev.com/ef4e847c615cc3fa778d84586578409d8d4f0895/ui/events/event.cc
[modify] https://crrev.com/ef4e847c615cc3fa778d84586578409d8d4f0895/ui/events/event.h
[modify] https://crrev.com/ef4e847c615cc3fa778d84586578409d8d4f0895/ui/events/event_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/13d4e1e80c19db9595d44b75ef684d9670b9c147

commit 13d4e1e80c19db9595d44b75ef684d9670b9c147
Author: moshayedi <moshayedi@chromium.org>
Date: Fri Jun 03 15:16:09 2016

Map ET_POINTER_MOVED to ET_MOUSE_DRAGGED when a mouse button is down.

BUG= 615094 

Review-Url: https://codereview.chromium.org/2033743003
Cr-Commit-Position: refs/heads/master@{#397710}

[modify] https://crrev.com/13d4e1e80c19db9595d44b75ef684d9670b9c147/ui/events/event.cc
[modify] https://crrev.com/13d4e1e80c19db9595d44b75ef684d9670b9c147/ui/events/event_unittest.cc

We have the typemap.