Add events component to ui_unittests dependencies when use_aura==1

We need this for the embedded build, otherwise the following tests don't link:

- event_dispatcher_unittest
- ozone/evdev/key_event_converter_unittest
- ozone/evdev/touch_event_converter_unittest

Review URL: https://codereview.chromium.org/79063002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236455 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236455