The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0cdf2f67e56e4050c9e437071723064a604e3272

commit 0cdf2f67e56e4050c9e437071723064a604e3272
Author: Maksim Sisov <msisov@igalia.com>
Date: Wed Nov 15 09:13:22 2017

[ozone/wayland] Use keyboard modifiers with pointer events.

This patch makes WaylandPointer use WaylandKeyboard::modifiers_.
When WaylandPointer receives an event from Wayland, it calls to
WaylandConnection::GetKeyboardModifiers, which returns
WaylandKeyboard::modifiers_. After that it creates a MouseEvent with
WaylandPointer::flags_, which include keyboard modifiers.

In order to make sure modifiers don't alter original bits of flags_,
the used modifiers are stored as keyboard_modifiers_ and flags_ are
tested in WaylandPointer::VerifyFlagsAfterMasking method by
excluding the modifiers and verifying the old flags are the
same as the newest ones after removing the modifiers.

By doing so, an events' consumer knows if pointer events were sent
during ctrl, shift or other modifier keys pressed at the same time.

Bug:  784393 
Change-Id: I7b75d289f65f5facb738981b6a95b361e0c6ecbc
Reviewed-on: https://chromium-review.googlesource.com/718097
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516649}
[modify] https://crrev.com/0cdf2f67e56e4050c9e437071723064a604e3272/ui/ozone/platform/wayland/wayland_connection.cc
[modify] https://crrev.com/0cdf2f67e56e4050c9e437071723064a604e3272/ui/ozone/platform/wayland/wayland_connection.h
[modify] https://crrev.com/0cdf2f67e56e4050c9e437071723064a604e3272/ui/ozone/platform/wayland/wayland_keyboard.h
[modify] https://crrev.com/0cdf2f67e56e4050c9e437071723064a604e3272/ui/ozone/platform/wayland/wayland_pointer.cc
[modify] https://crrev.com/0cdf2f67e56e4050c9e437071723064a604e3272/ui/ozone/platform/wayland/wayland_pointer.h