The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ab3540641865b8290b25af8f169b905e8e434d8e

commit ab3540641865b8290b25af8f169b905e8e434d8e
Author: chaopeng <chaopeng@chromium.org>
Date: Thu Mar 22 23:25:50 2018

Cleanup the const ref parameter in HWNDMessageHandlerDelegate

The patch move the const ref event parameters to pointer parameters
in HWNDMessageHandlerDelegate. It can save the conversion in
DesktopWindowTreeHostWin.

Bug:  823860 
Change-Id: Ic4055fa3b8c8c977b9123e5b5360b483a0eec746
Reviewed-on: https://chromium-review.googlesource.com/976089
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Jianpeng Chao <chaopeng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545286}
[modify] https://crrev.com/ab3540641865b8290b25af8f169b905e8e434d8e/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
[modify] https://crrev.com/ab3540641865b8290b25af8f169b905e8e434d8e/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
[modify] https://crrev.com/ab3540641865b8290b25af8f169b905e8e434d8e/ui/views/win/hwnd_message_handler.cc
[modify] https://crrev.com/ab3540641865b8290b25af8f169b905e8e434d8e/ui/views/win/hwnd_message_handler_delegate.h