The animation videos are changing to have a white background, so we want to
match that in the background color to avoid horizontal bands of the current
grey background color on the edges of the new videos. We're also adding a
divider between the video and the content beneath it.
This CL also includes the new illustration video for the launcher gesture.
Fixes: 77861241
Fixes: 77474484
Test: manual (visit all entries in Settings->System->Gestures, as well as
Settings->Display->Adaptive brightness)
Change-Id: I976782645c9431d40e005960b80353a7da2b89b8
The illusteration video is not included yet.
Merged-In: I7f2b2f3251a795dfd74dbbb442692e42a5a2966e
Bug: 77549883
Test: Unit tests and Manual test
Change-Id: I04f01f0814f16e4e006291e61ddb07cea8e7c0d6
