Move ui_base_features into separate component

ui_base_features is currently part of ui/base:base. Despite the name,
ui/base:base is not the bottom layer in ui/, as it depends on certain
components such as ui/events:events.

In order to use ui_base_features to modify behavior in ui/events:events
we'll factor out ui_base_features into it's own component (it has to
be a component as it is comprised mainly of global variables).

Bug: 933396
Change-Id: I9c4d869001f70135af8fa2e3f6fc12c9ddd06223
Reviewed-on: https://chromium-review.googlesource.com/c/1478033
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Daniel Libby <dlibby@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#633458}
2 files changed