Fix audio ducking support for the output side on Windows.
The input side is now correctly opening up the communication device and we're
getting the appropriate ducking behavior whether or not the default
communication device also the default console device.

What was missing was to also open up the render streams as a communication
device for associated output streams (associated to the communication input
streams that is).
If we don't do that, the communication output streams would also get ducked,
thus making the whole exercise futile.

BUG=347531
NOTRY=True

Review URL: https://codereview.chromium.org/185863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255042 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255042