ozone: evdev: Move MouseButtonMap usage during dispatch to EventFactoryEvdev
This is part of a series moving IO on evdev devices to a fast thread,
since UI thread is too slow for the cursor.
The mouse button map is a UI thread object, so move all of the mouse
processing that needs button map information outside of the
device-specific object. Devices no longer get a MouseButtonMapEvdev*
since they will execute on a different thread.
BUG=449710
TEST=boot link_freon & click mouse
Review URL: https://codereview.chromium.org/
872683006
Cr-Commit-Position: refs/heads/master@{#313425}