As explained in  issue 755248 , the root cause is invalid audio parameters sent across processes. Thus, removing the webcam label.

The original fix to  issue 755248  already includes one test to cover the problem, but it's a good idea to look at all places were media::AudioParameters are being sent across process as a consequence of the removal of content::AudioDeviceParameters and add more regression tests if applicable.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/64f37d1e31dfe3315477f940f9a0cd48c4bc16b4

commit 64f37d1e31dfe3315477f940f9a0cd48c4bc16b4
Author: Chandan Padhi <c.padhi@samsung.com>
Date: Wed Aug 16 19:56:08 2017

Ensure media::AudioParameters used for |input| are valid

Default-constructed media::AudioParameters are invalid and therefore
not serializable. Such parameters if sent across processes result in
deserialization failures.

Bug:  755578 
Change-Id: Ia5ae18fbc4862dab4e1c5fbf8496c1bd6009b7c6
Reviewed-on: https://chromium-review.googlesource.com/616548
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Chandan Padhi <c.padhi@samsung.com>
Cr-Commit-Position: refs/heads/master@{#494908}
[modify] https://crrev.com/64f37d1e31dfe3315477f940f9a0cd48c4bc16b4/content/browser/renderer_host/media/media_stream_manager.cc
[modify] https://crrev.com/64f37d1e31dfe3315477f940f9a0cd48c4bc16b4/content/public/common/media_stream_request.cc
[modify] https://crrev.com/64f37d1e31dfe3315477f940f9a0cd48c4bc16b4/content/renderer/media/mock_media_stream_dispatcher.cc

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

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