Revert 235139 "Fix cancelling of device enumeration requests."
> Fix cancelling of device enumeration requests.
>
> TEST= Log using --vmodule=media_stream_manager*=3,media_stream_dispatcher*=3 and make sure the log print out media_stream_manager.cc(316)]CancelRequest(
> after
> MediaStreamDispatcher::StopEnumerateDevices() while using the webcam on youtube.com/my_webcam?privacy=public
>
> BUG=317534
> R=xians@chromium.org
>
> Review URL: https://codereview.chromium.org/
72683002
TBR=perkj@chromium.org
Review URL: https://codereview.chromium.org/
74753005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235678 0039d316-1c4b-4281-b951-d872f2087c98