Add User Actions for site muting

This CL adds mute and unmute User Actions for each of the different
ways the user can change the sound setting.

Bug: 780917
Change-Id: Ica33368ef7c5a1cefe2cf0acd83cba99b77bae1b
Reviewed-on: https://chromium-review.googlesource.com/752690
Reviewed-by: Steven Holte <[email protected]>
Reviewed-by: Theresa <[email protected]>
Reviewed-by: Scott Violet <[email protected]>
Reviewed-by: Mounir Lamouri <[email protected]>
Commit-Queue: Tommy Steimel <[email protected]>
Cr-Commit-Position: refs/heads/master@{#514572}
7 files changed