Merge M48: "Ensure both default audio device IDs are handled for creation."

Merge M48: "Ensure both default audio device IDs are handled for creation."

With the introduction of the AudioOutputDeviceEnumerator we started
creating AudioOutputControllers with kDefaultDeviceId, but the proxy
creation code did not merge these cases correctly -- so streams
which should have been default were stuck on a single device.

This adds a test for this behavior, though it unfortunately relies
on some internal AudioManager details -- we've seen similar bugs
like this in the past, so its clear we need something.

BUG=557620
TEST=switched headphones works, new unittest.

Review URL: https://codereview.chromium.org/1480523004

Cr-Commit-Position: refs/heads/master@{#361875}
(cherry picked from commit 6543b17d2aa62107125c34ec2550fd46181c316e)

Committed: https://chromium.googlesource.com/chromium/src/+/e1dbf162c1c043f4bb6f0bf77d99076837da33c5

[DaleCurtis, 2015-11-30 19:49:29]

Description was changed from

==========
Merge M48: "Ensure both default audio device IDs are handled for creation."

With the introduction of the AudioOutputDeviceEnumerator we started
creating AudioOutputControllers with kDefaultDeviceId, but the proxy
creation code did not merge these cases correctly -- so streams
which should have been default were stuck on a single device.

This adds a test for this behavior, though it unfortunately relies
on some internal AudioManager details -- we've seen similar bugs
like this in the past, so its clear we need something.

BUG=557620
TEST=switched headphones works, new unittest.

Review URL: https://codereview.chromium.org/1480523004

Cr-Commit-Position: refs/heads/master@{#361875}
(cherry picked from commit 6543b17d2aa62107125c34ec2550fd46181c316e)
==========

to

==========
Merge M48: "Ensure both default audio device IDs are handled for creation."

With the introduction of the AudioOutputDeviceEnumerator we started
creating AudioOutputControllers with kDefaultDeviceId, but the proxy
creation code did not merge these cases correctly -- so streams
which should have been default were stuck on a single device.

This adds a test for this behavior, though it unfortunately relies
on some internal AudioManager details -- we've seen similar bugs
like this in the past, so its clear we need something.

BUG=557620
TEST=switched headphones works, new unittest.

Review URL: https://codereview.chromium.org/1480523004

Cr-Commit-Position: refs/heads/master@{#361875}
(cherry picked from commit 6543b17d2aa62107125c34ec2550fd46181c316e)

Committed:
https://chromium.googlesource.com/chromium/src/+/e1dbf162c1c043f4bb6f0bf77d99...
==========

[DaleCurtis, 2015-11-30 19:49:32]

Committed patchset #1 (id:1) manually as
e1dbf162c1c043f4bb6f0bf77d99076837da33c5.