Fix volume button state

The spec requires the volume button to be grayed out when muted and
blue when not muted. The current behavior is the reverse.

Bug: 863488
Test: manual
Change-Id: Id2c794484761bbb46eef4ab805e77eed38b45b9c
Reviewed-on: https://chromium-review.googlesource.com/c/1448996
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Auto-Submit: Vladislav Kaznacheev <kaznacheev@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628811}
1 file changed