Revert of Gardening: Revert "Use AudioStreamMonitor to control power save blocking...

Revert of Gardening: Revert "Use AudioStreamMonitor to control power save blocking." (patchset #1 id:1 of https://codereview.chromium.org/562863002/)

Reason for revert:
Bugs should be fixed now... will CQ this revert.

Original issue's description:
> Gardening: Revert "Use AudioStreamMonitor to control power save blocking."
>
> This reverts commit 484d29dcb45ca362fc9049c37dd3a51e11492f14.
>
> This patch made media/media-controller-playbackrate.html test crash on DEBUG.
>
> it crashes at content/browser/web_contents/web_contents_impl.cc:4296 on DCHECK
> Looks like AddMediaPlayerEntry was called twice for the same player_cookie
>
> It is not clear how it happens due to async nature of the notification.
> The author is sleeping at the moment, so I decided to roll back the patch.
>
> BUG=
> TBR=dalecurtis@chromium.org
>
> Committed: https://crrev.com/0381a74131887eb13b5d457cce756fb7066411ea
> Cr-Commit-Position: refs/heads/master@{#294370}

TBR=loislo@chromium.org,jam@chromium.org,miu@chromium.org,scherkus@chromium.org
BUG=43667, 367785

Review URL: https://codereview.chromium.org/569713002

Cr-Commit-Position: refs/heads/master@{#294630}