Currently, it takes its parameters (sampleRate, echoCancellation...) from its first client.
But it should really be the last client having either been created or been applying constraints.
Created attachment 309377 [details]
Attachment 309377 [details] did not pass style-queue:
ERROR: Source/WebCore/platform/mediastream/mac/CoreAudioCaptureSource.cpp:253: Missing space after , [whitespace/comma] 
Total errors found: 1 in 4 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Created attachment 309380 [details]
Comment on attachment 309380 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=309380&action=review
> + Adding sampleRate, volume and echoCancellation parameters to the shared audio unit.
> + Setting default values when creating the shared audio unit and using those for the creation of new sources.
Nit: "Adding" => "Add", "Setting" => "Set", "using" => "use"
> + Checking valid sample rates when trying to apply a sample rate.
Nit: "Checking" => "Check"
Created attachment 309414 [details]
Comment on attachment 309414 [details]
Clearing flags on attachment: 309414
Committed r216455: <http://trac.webkit.org/changeset/216455>
All reviewed patches have been landed. Closing bug.