Speaker button in tabs should mute or play audio for current tab

Description

When a site is playing audio, the tab that the audio is playing in will show a small speaker icon. You should be able to click this to mute the tab. Unfortunately, that is not working on DEV and BETA channels (BETA worked with 0.56.7, RELEASE works fine). If you right click and choose Mute from the context menu, it does work

Test plan / Steps to Reproduce

1. Visit a site that plays audio (ex: http://beirutnights.com/)
2. Ensure audio is playing and that speaker icon shows for the tab
3. Try clicking the speaker icon and notice that nothing happens

Actual result:

Speaker button does absolutely nothing

Expected result:

Speaker button should toggle (showing a speaker with a cross through it)

Reproduces how often:

100%

Brave version (brave://version info)

Brave	0.57.4 Chromium: 71.0.3578.31 (Official Build) dev (64-bit)
Revision	c88fdf2a4ce19a713615ca4fbde7a0d0b5fe2363-refs/branch-heads/3578@{#427}
OS	Mac OS X

Brave	0.57.6 Chromium: 71.0.3578.31 (Official Build) beta(64-bit)
Revision	c88fdf2a4ce19a713615ca4fbde7a0d0b5fe2363-refs/branch-heads/3578@{#427}
OS	Mac OS X

Reproducible on current release:

• Does it reproduce on brave-browser dev/beta builds? ONLY reproduces on DEV and BETA. RELEASE work fine

[NotAmaan]

Can this be disabled with a flag or something? I usually have some YouTube music stream playing while I work and tend to Pin that tab. Now I can never switch to the pinned tab playing audio without muting it once or twice.

[bsclifton]

Code merged - our next Nightly build will have this fixed 😄👍